DÄ internationalArchive16/2018The Risks Associated With Obesity in Pregnancy

Review article

The Risks Associated With Obesity in Pregnancy

Dtsch Arztebl Int 2018; 115(16): 276-83; DOI: 10.3238/arztebl.2018.0276

Stubert, J; Reister, F; Hartmann, S; Janni, W

Background: Approximately one-third of all women of childbearing age are overweight or obese. For these women, pregnancy is associated with increased risks for both mother and child.

Methods: This review is based on pertinent publications retrieved by a selective search of PubMed, with special attention to current population-based cohort studies, systematic reviews, meta-analyses, and controlled trials.

Results: Obesity in pregnancy is associated with unfavorable clinical outcomes for both mother and child. Many of the risks have been found to depend linearly on the body-mass index (BMI). The probability of conception declines linearly, starting from a BMI of 29 kg/m2, by 4% for each additional 1 kg/m2 of BMI (hazard ratio 0.96, 95% confidence interval: [0.91; 0.99]). A 10% increase of pregravid BMI increases the relative risk of gestational diabetes and that of preeclampsia by approximately 10% each. A 5 kg/m2 increase of BMI elevates the relative risk of intrauterine death to 1.24 [1.18; 1.30]. An estimated 11% of all neonatal deaths can be attributed to the consequences of maternal overweight and obesity. Nonetheless, in most randomized controlled trials, nutritional and lifestyle interventions did not bring about any clinically relevant reduction in the incidence of gestational diabetes and fetal macrosomia.

Conclusion: The risks associated with obesity in pregnancy cannot necessarily be influenced by intervention. Preventive measures aimed at normalizing body weight before a woman becomes pregnant are, therefore, all the more important.

The prevalence of obesity (body mass index [BMI] ≥ 30 kg/m2) among young women has increased in Germany over the last two decades. According to a survey conducted in 2013, 9.6% (n = 7116; 95% confidence interval (CI): [7.2; 12.7]) of all women between 18 and 29 years were obese (1). In the age group from 30 to 39 years, the prevalence increases to 17.9% [14.0; 22.7] (1). Class III obesity (BMI ≥ 40 kg/m2) affects 0.9% [0.3; 2.7] of the 18- to 29-year-old and 2.3% [1.1; 4.6%] of the 30- to 39-year-old women (1). Combined, about one third of all women of reproductive age are overweight (BMI ≥ 25 to <30 kg/m2, prevalence between 30 and 38%) or obese (1). Maternal and fetal morbidity risks associated with pregnancy will be discussed in the following.

Methods

A selective search primarily of the English literature was conducted in the PubMed database, using the following search terms: “obesity”, “pregnancy”, “female fertility”, “miscarriage”, “still birth”, “mortality”, “morbidity”, “weight gain”. Altogether 4002 hits were obtained for the past ten years up to and including December 2017.

Population-based cohort studies, randomized controlled trials, systematic reviews, and meta-analyses were preferentially included in the analysis. Relevant older papers identified in references or by targeted keyword search were also included.

Obesity and the desire to have children

Obesity-related hyperinsulinemia und subsequent hyperandrogenemia increase the risk for anovulatory cycles (2). The time until pregnancy occurs is longer in obese women compared to women of normal weight (3, e1e3). The chance of conception within one year is already reduced starting at a BMI of 26 kg/m2 (89.4% with a BMI of 20–25kg/m2 versus 82.7% with a BMI >25 kg/m2; n = 10 903) (4). Women with comorbidity were excluded from the analysis. The effect remained significant even after adjustment for possible confounding factors, such as age, parity as well as regularity and duration of the menstrual cycle (odds ratio [OR]: 0.77 [0.70; 0.84]). Thus, reduced fertility associated with increasing BMI cannot only be attributed to menstrual irregularities (4, 5).

A study on women with regular ovulations desiring to have children (after exclusion of tubal and androgenic abnormalities, n = 3029) found that within one year 17% of subjects had a spontaneous pregnancy not ending in miscarriage (5). The likelihood of conception decreased in a linear fashion by 4% per 1 kg/m2 weight gain, starting from a BMI of 29 kg/m2; this finding remained significant even after adjusting for potential confounders (age, duration of desiring a child, pregnancy, smoking, sperm motility) (hazard ratio [HR]: 0.96 [0.91; 0.99]) (5).

Likewise, obesity had a negative impact on pregnancy rate and implantation rate after embryo transfer in autologous in vitro fertilization (IVF) (6, e4). A registry study from the US analyzing 239 127 IVF cycles showed that pregnancy rates and implantation rates declined by 1% with every increase in BMI by 5 kg/m2 (6).

Maternal risks over the course of pregnancy

The risk of pregnancy-associated disorders increases with increasing severity of obesity (Table 1) (712). A 10% difference in pre-pregnancy BMI is associated with an at least 10% change in relative risk of preeclampsia and gestational diabetes, respectively (10). The obesity-associated increase in risk of not primarily pregnancy-related diseases is usually less pronounced (79, 12). Over the long term (≥ 10 years), a pre-pregnancy BMI >25 kg/m2 is associated with an increased risk of manifestation of diabetes mellitus and cardiac disease. Gestational weight gain of more than 15 kg increases the risk of becoming obese later in life (13).

Risks of maternal diseases in pregnancy in relation to body mass index
Risks of maternal diseases in pregnancy in relation to body mass index
Table 1
Risks of maternal diseases in pregnancy in relation to body mass index

Fetal and neonatal risks

A pooled analysis of six studies comparing obese (n = 3800) with normal-weight women (n = 17 146) found an increased miscarriage rate after spontaneous conception (13.6% versus 10.7%, OR: 1.31 [1.18; 1.46]) (14). Likewise, recurrent miscarriage was more common in obese women (0.4% versus 0.1%, OR: 3.51 [1.03; 12.01]). A chromosomal analysis showed that euploid miscarriages occurred more frequently in obese women compared to normal-weight women (58% [18/31] versus 37% [32/86], risk ratio [RR]: 1.63 [1.08; 2.47], p = 0.02) (15). Maternal age and endocrine, autoimmune and inflammatory diseases were excluded as causative factors (15).

The prevalence of fetal malformations was significantly correlated with the severity of obesity (Table 2) and the risk increase was independent of gestational diabetes (16). Apart from that, a meta-analysis comprising 18 studies reported the following obesity-associated increases in risk for specific malformations:

  • Spina bifida (n = 863, OR: 2.24 [1.86; 2.69], p <0.001)
  • Cardiac septal defects (n = 3483, OR: 1.20 [1.09; 1.31], p <0.001)
  • Anorectal atresia (n = 273, OR: 1.48 [1.12; 1.97], p = 0.006
  • Hydrocephalus (n = 188, OR: 1.68 [1.19; 2.36], p = 0.003) (17).
Congenital fetal malformation risks associated with maternal obesity
Congenital fetal malformation risks associated with maternal obesity
Table 2
Congenital fetal malformation risks associated with maternal obesity

Only the risk of gastroschisis was lower with obesity (n = 379, OR: 0.17 [0.10; 0.30)], p <0.001). Furthermore, a cohort study evaluating 41 013 singleton pregnancies found that obesity increased the risk of eye anomalies (n = 1 versus n = 12; adjusted OR 6.30 [1.58; 25.08)], p = 0.009) (e5).

However, it has to be taken into account that ultrasound sensitivity was reduced due to unfavorable physical scanning conditions (e6). The decrease in fetal chromosomal fraction associated with obesity results in reduced detection rates for chromosomal aberrations, regardless of gestational age, in non-invasive prenatal testing (NIPT) too (e7).

The risk of intrauterine fetal death (IUFD) is increased in obese compared to normal-weight women (Table 3) (9). A meta-analysis calculated an adjusted risk ratio of 1.24 for a BMI increase by 5 kg/m2 [1.18; 1.30] (18). While IUFD in women with a BMI of 20 kg/m2 was observed in 0.4% of cases, the prevalence of IUFD in women with a BMI of 30 kg/m2 was 0.59% [0.55; 0.63]. In the majority of cases, IUFD was caused by a combination of abnormal placental function and arterial hypertension (e8).

Miscarriage risk: fetal and neonatal outcomes in relation to maternal body mass index
Miscarriage risk: fetal and neonatal outcomes in relation to maternal body mass index
Table 3
Miscarriage risk: fetal and neonatal outcomes in relation to maternal body mass index

Similarly, maternal obesity is associated with an elevated postnatal mortality risk (first year of life) which increases with increasing BMI (Table 3) (19). The effect was more pronounced in term versus preterm neonates and had an effect on both early (≤ 28 days after delivery) and late mortality (>28 days after delivery). Even after women with concomitant hypertension and diabetes had been excluded, the association was still present: When comparing normal-weight versus BMI ≥40 kg/m2 women, the adjusted OR was 2.24 [95% CI: 1.65; 3.03]. The authors calculated that 11% of deaths were associated with complications caused by overweight and obesity. Thus, with an annual infant mortality of about 2400 cases in Germany, 264 deaths could have been avoided. A sibling study confirmed the significance of maternal obesity as a risk factor for IUFD and postnatal mortality, regardless of genetic predisposition or familial factors (e9). Likewise, in initially normal-weight women a weight gain ≥2 kg/m2 was associated with an increased risk of IUFD and postnatal mortality (20). Weight loss from an initial BMI of ≥ 25 kg/m2 reduced the risk of neonatal mortality during the first 28 days after birth (20). Other studies confirmed the association between obesity and risk of IUFD and postnatal mortality (7, e10e12).

Apart from an increased risk of asphyxia—which is also reflected in the increased infant cerebral palsy rates—causative factors included congenital anomalies and sudden infant death syndrome (19, e13, e14).

The preterm birth rate—both spontaneous and medically indicated due to pregnancy-associated conditions—is increased in obesity and contributes to the unfavorable neonatal outcome (21, 22, e15). The risk of medically indicated early preterm birth is primarily increased due to hypertensive and diabetic pregnancy complications (22). This risk is further increased in patients with gestational weight gain which is above the Institute of Medicine’s recommendations of 5 to 9 kg from a BMI ≥30 kg/m2 (meta-analysis with n = 3892, adjusted OR: 1.54 [1.09; 2.16]) (23, 24). The situation is similar for weight gain between two pregnancies. In women with first pregnancy BMI <25, the risk of spontaneous preterm birth (32 to 36 weeks’ gestation) increases by adjusted 18% when the BMI increases by ≥4 kg/m2 compared to baseline level [5; 33%], p = 0.007, n = 305 953) (e16).

Fetal macrosomia and postnatal metabolic consequences

Maternal obesity increases the risk of fetal macrosomia, as demonstrated by the results of a meta-analysis including 21 studies: 13.4% with obesity (n = 31 756) versus 7.8% with normal weight (n = 57 392, pooled OR: 2.11 [1.97; 2.27]) (25). Here again, maternal gestational weight gain was an additional independent risk factor (e17, e18). Neonates of obese mothers had a higher percentage of adipose tissue (e19, e20). A study evaluating 112 309 deliveries of women without chronic disease prior to pregnancy showed that the percentage of fetal macrosomia (“large for gestational age“, LGA) rose with increasing maternal BMI, amounting to 17% (538/3105) among ≥40 kg/m2 women (2.76% of the cohort) compared to 8% (5272/66 463) among normal-weight mothers (RR: 2.32 [2.14; 2.52], p <0.001) (7). This association remained even after exclusion of all cases with gestational hypertensive disease and gestational diabetes (14.7% [n = 327] in pregnant women with class III obesity versus 7.9% [n = 4863] with normal weight, RR: 2.04 [1.83; 2.26], p <0.001). Further studies confirmed that obesity is a risk factor for fetal macrosomia, independent of a diabetic metabolic state (26, e21). The pathogenesis of fetal macrosomia is complex. On the one hand, macrosomia appears to be the consequence of increased maternal blood glucose levels, resulting from obesity-related insulin resistance which can already be detected below the diagnostic threshold for gestational diabetes (26, 27, e22). This is supported by the close correlation between maternal fasting glucose levels and fetal weight (23, 28, e17). On the other hand, however, the increase in percentage of adipose tissue in the neonate can only be explained to a limited extent by the increased availability of metabolic substrates (28). After including placental mass as a covariate in multiple regression analysis, BMI-related metabolic changes correlating with neonatal body fat mass were no longer significant (e23). This highlights the important role of the placenta as a nutritive sensor, actively influencing the metabolic regulation of maternofetal interactions (e24, e25).

Fetal macrosomia, maternal obesity and excessive weight gain during pregnancy are associated with later obesity in childhood and adolescence (e26, e27). As early as at age 6 years, children of women who were obese before they became pregnant had more often a cardiometabolic risk profile compared to children of normal-weight mothers: 22.4% (54/404) versus 8.3% (144/2789), p <0.01; OR: 3.0 [2.09; 4.34]) (e28). After adjusting for the children’s BMIs, these differences were no longer significant; thus, the changes (parameters assessed: android fat distribution pattern, blood pressure, blood lipid levels, serum insulin and C-peptide levels) are significantly influenced by the increased risk of weight gain these children are exposed to. Similar results were found for maternal weight gain during early pregnancy (e29). These associations can still be demonstated at age 17 years (e29).

Intra- and post-partum risks

The risks culminate at the time of delivery and apply to mother and infant (Table 4). The likelihood of vaginal delivery decreases with increasing obesity (8, 11, e30). Even though cesarean sections are more commonly performed in obese mothers (79), attempts of vaginal delivery are successful in 73% of primiparas and 94% of multiparas (e31). Conditions underlying the increased cesarean section rate include preeclampsia, fetal distress, cephalopelvic disproportion, and failure to progress in labor (11, e32). However, due to wound infection and wound healing abnormalities, surgery-associated morbidity is also increased in obese women (7, 8, 11). Epidural analgesia is often unsuccessful (e33). Early administration of epidural anesthesia can be advantageous as, in case an emergency cesarean section is indicated at a later stage of labor, it avoids the risks associated with general anesthesia (e34).

Obstetric outcome parameters: risk in relation to pre-pregnancy body mass index
Obstetric outcome parameters: risk in relation to pre-pregnancy body mass index
Table 4
Obstetric outcome parameters: risk in relation to pre-pregnancy body mass index

The risk of shoulder dystocia is not or only insignificantly increased by obesity alone (8, 9). The largest study on this risk found a significant association between BMI and shoulder dystocia (incidence in the total population: 0.9%, OR: 2.0 [1.73; 2.37] for BMI ≥35 kg/m2) (9). However, after adjustment this association was no longer significant (adjusted OR: 1.2 [0.98; 1.37]). The covariates birth weight, gestational diabetes, and gestational age were individually not significant; thus, it appears that the risk increase observed without adjustment is the result of the interaction of these risk factors (9).

Intervention options for maternal obesity

The eTable provides an overview over current randomized controlled trials and Table 5 over obesity-related meta-analyses aiming to improve pregnancy outcomes. Lifestyle interventions comprise dietary changes and physical activity. In women desiring to have children, these interventions can increase ovulation and spontaneous conception rates (29, 30, e35, e36). However, patients already scheduled for assisted reproduction treatment did not benefit from weight reduction (30).

Meta-analyses on the reduction of obesity-associated pregnancy risks (selection
Meta-analyses on the reduction of obesity-associated pregnancy risks (selection
Table 5
Meta-analyses on the reduction of obesity-associated pregnancy risks (selection
Randomized controlled trials on the reduction of obesity-associated pregnancy risks (selection)
Randomized controlled trials on the reduction of obesity-associated pregnancy risks (selection)
eTable
Randomized controlled trials on the reduction of obesity-associated pregnancy risks (selection)

At best, a weight reduction of 10 to 15% within one year can be expected from lifestyle interventions. Weight loss of 30 to 40% is often achieved in the first year after bariatric surgery (e37). The largest published case–control study evaluating the effect of bariatric surgery found significant reductions in the prevalences of gestational diabetes and fetal macrosomia, but also an increased risk of fetal hypotrophy (15.6% [92/590] versus 7.6% [178/2336], adjusted OR: 2.2 [1.64; 2.95], p <0.001) (e38). Furthermore, a trend towards increased perinatal mortality was observed (1.7% [10/596] versus 0.7% [17/2356], adjusted OR: 2.39 [0.98; 5.85], p = 0.06) (e38). In another analysis, status post bariatric surgery was associated with an increased risk of preterm birth >32 weeks’ gestation (7.3% [139/1917] versus 5.7% [369/6496], adjusted OR: 1.30 [1.05; 1.60], p = 0.01) (e37, e39). Matching criteria for the control group included preoperative BMI, age, and parity. The groups were homogeneous with regard to comorbidities, such as diabetes mellitus and cardiovascular disease. The cause(s) underlying the observed risk increase remain unclear; impaired nutrition due to malassimilation and metabolic-endocrine adjustments due to the changed fat distribution pattern have been discussed as possible explanations (e37, e40, e41).

Weight loss during pregnancy is associated with a heightened risk of neonatal hypotrophy (e42, e43). Thus, despite the inconsistency of the available data (e44), weight reduction during pregnancy is not usually recommended (e34, e43). By contrast, weight loss between 2 pregnancies has a positive effect on neonatal outcomes (e45). After delivery, however, mothers are generally poorly motivated to actively reduce weight (e46).

Metformin treatment of obese pregnant women was evaluated in 2 randomized controlled trials where it reduced weight gain during pregnancy but did not lower the risk of gestational diabetes and neonatal macrosomia (31, 32).

Gestational weight gain was also reduced by lifestyle interventions; however, no or no clinically relevant reduction of maternal or fetal morbidity was observed in these studies (3339, e47e51). However, it appears that intensive and supervised physical activity started early in pregnancy (during first 3 months) can reduce maternal blood glucose levels and the rate of gestational diabetes to a clinically relevant degree (40).

Conclusion

Obesity-related maternal and fetal increases in morbidity during pregnancy are well supported by evidence from studies. Obesity is a risk factor independent of comorbidities such as diabetes. The same applies to excessive weight gain during pregnancy. There is growing evidence that the placenta plays an important role in the regulation of fetal growth. Treatment strategies appear to be promising, provided the following conditions are met:

  • High-level adherence and monitoring of intervention by supervision of the training program
  • Start of intervention prior to or concomitant with placental development to prevent irreversible negative metabolic conditioning.

In principal, weight normalization prior to getting pregnant is advantageous. Ultimately, long-term reduction of maternal and fetal morbidity can only be achieved by dietary and lifestyle changes maintained beyond pregnancy.

Conflict of interest statement
The authors declare that no conflict of interests exists.

Manuscript received on 20 June 2017; revised version accepted on 5 February 2018.

Translated from the original German by Ralf Thoene, MD.

Corresponding author
PD Dr. med. habil. Johannes Stubert
Universitätsfrauenklinik und Poliklinik am Klinikum Südstadt Rostock
Südring 81, 18059 Rostock, Germany
johannes.stubert@uni-rostock.de

Supplementary material
For eReferences please refer to
www.aerzteblatt-international.de/ref1618

eTable:
www.aerzteblatt-international.de/18m0276

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Villamor E, Tedroff K, Peterson M, et al.: Association between maternal body mass index in early pregnancy and Incidence of cerebral palsy. JAMA 2017; 317: 925–36 CrossRef MEDLINE
e15.
Shaw GM, Wise PH, Mayo J, et al.: Maternal prepregnancy body mass index and risk of spontaneous preterm birth. Paediatr Perinat Epidemiol 2014; 28: 302–11 CrossRef MEDLINE
e16.
Villamor E, Cnattingius S: Interpregnancy weight change and risk of preterm delivery. Obesity (Silver Spring) 2016; 24: 727–34 CrossRef MEDLINE
e17.
Sommer C, Sletner L, Morkrid K, Jenum AK, Birkeland KI: Effects of early pregnancy BMI, mid-gestational weight gain, glucose and lipid levels in pregnancy on offspring‘s birth weight and subcutaneous fat: a population-based cohort study. BMC Pregnancy Childbirth 2015; 15: 84 CrossRef MEDLINE PubMed Central
e18.
Starling AP, Brinton JT, Glueck DH, et al.: Associations of maternal BMI and gestational weight gain with neonatal adiposity in the Healthy Start study. Am J Clin Nutr 2015; 101: 302–9 CrossRef MEDLINE PubMed Central
e19.
Hull HR, Dinger MK, Knehans AW, Thompson DM, Fields DA: Impact of maternal body mass index on neonate birthweight and body composition. Am J Obstet Gynecol 2008; 198: 416. e1–6 CrossRef MEDLINE
e20.
Sewell MF, Huston-Presley L, Super DM, Catalano P: Increased neonatal fat mass, not lean body mass, is associated with maternal obesity. Am J Obstet Gynecol 2006; 195: 1100–3 CrossRef MEDLINE
e21.
Ehrenberg HM, Mercer BM, Catalano PM: The influence of obesity and diabetes on the prevalence of macrosomia. Am J Obstet Gynecol 2004; 191: 964–8 CrossRef MEDLINE
e22.
Harmon KA, Gerard L, Jensen DR, et al.: Continuous glucose profiles in obese and normal-weight pregnant women on a controlled diet: metabolic determinants of fetal growth. Diabetes Care 2011; 34: 2198–204 CrossRef MEDLINE PubMed Central
e23.
Friis CM, Qvigstad E, Paasche Roland MC, et al.: Newborn body fat: associations with maternal metabolic state and placental size. PLoS One 2013; 8: e57467.
e24.
Jansson T, Powell TL: Placental amino acid transporters. In: Moffett A, Barker DJP, Burton GJ, Thornburg K (eds.): The Placenta and Human Developmental Programming. Cambridge: Cambridge University Press 2010; 147–60.
e25.
Wright C, Sibley CP: Placental transfer in health and disease. In: Kay HH, Nelson DM, Wang Y (eds.): The placenta: from development to disease. Oxford, UK: Wiley-Blackwell 2011; p. 66–74 CrossRef MEDLINE
e26.
Castillo H, Santos IS, Matijasevich A: Relationship between maternal pre-pregnancy body mass index, gestational weight gain and childhood fatness at 6–7 years by air displacement plethysmography. Matern Child Nutr 2015; 11: 606–17 CrossRef MEDLINE PubMed Central
e27.
Woo Baidal JA, Locks LM, Cheng ER, Blake-Lamb TL, Perkins ME, Taveras EM: Risk factors for childhood obesity in the first 1,000 days: a systematic review. Am J Prev Med 2016; 50: 761–79 MEDLINE
e28.
Gaillard R, Steegers EA, Duijts L, et al.: Childhood cardiometabolic outcomes of maternal obesity during pregnancy: the Generation R Study. Hypertension 2014; 63: 683–91 CrossRef MEDLINE
e29.
Gaillard R, Welten M, Oddy WH, et al.: Associations of maternal prepregnancy body mass index and gestational weight gain with cardio-metabolic risk factors in adolescent offspring: a prospective cohort study. BJOG 2016; 123: 207–16 CrossRef CrossRef
e30.
Chu SY, Kim SY, Schmid CH, et al.: Maternal obesity and risk of cesarean delivery: a meta-analysis. Obes Rev 2007; 8: 385–94 CrossRef MEDLINE
e31.
Clark-Ganheart CA, Reddy UM, Kominiarek MA, Huang CC, Landy HJ, Grantz KL: Pregnancy outcomes among obese women and their offspring by attempted mode of delivery. Obstet Gynecol 2015; 126: 987–93 CrossRef MEDLINE PubMed Central
e32.
Kawakita T, Reddy UM, Landy HJ, Iqbal SN, Huang CC, Grantz KL: Indications for primary cesarean delivery relative to body mass index. Am J Obstet Gynecol 2016; 215: 515 e1–9.
e33.
Dresner M, Brocklesby J, Bamber J: Audit of the influence of body mass index on the performance of epidural analgesia in labour and the subsequent mode of delivery. BJOG 2006; 113: 1178–81 CrossRef MEDLINE
e34.
ACOG Practice Bulletin No 156: Obesity in pregnancy. Obstet Gynecol 2015; 126: e112–26 CrossRef MEDLINE
e35.
Legro RS, Dodson WC, Kunselman AR, et al.: Benefit of delayed fertility therapy with preconception weight loss over immediate therapy in obese women with PCOS. J Clin Endocrinol Metab 2016; 101: 2658–66 CrossRef MEDLINE PubMed Central
e36.
van Oers AM, Groen H, Mutsaerts MA, et al.: Effectiveness of lifestyle intervention in subgroups of obese infertile women: a subgroup analysis of a RCT. Hum Reprod 2016; 31: 2704–13 CrossRefMEDLINE
e37.
Legro RS: Mr. Fertility Authority, tear down that weight wall! Hum Reprod 2016; 31: 2662–4 CrossRefMEDLINE PubMed Central
e38.
Johansson K, Cnattingius S, Naslund I, et al.: Outcomes of pregnancy after bariatric surgery. N Engl J Med 2015; 372: 814–24 CrossRef MEDLINE
e39.
Stephansson O, Johansson K, Naslund I, Neovius M: Bariatric surgery and preterm birth. N Engl J Med 2016; 375: 805–6 CrossRef MEDLINE PubMed Central
e40.
Caughey AB: Bariatric surgery before pregnancy—is this a solution to a big problem? N Engl J Med 2015; 372: 877–8 CrossRef MEDLINE
e41.
Guelinckx I, Devlieger R, Donceel P, et al.: Lifestyle after bariatric surgery: a multicenter, prospective cohort study in pregnant women. Obes Surg 2012; 22: 1456–64 CrossRef MEDLINE
e42.
Beyerlein A, Schiessl B, Lack N, von Kries R: Associations of gestational weight loss with birth-related outcome: a retrospective cohort study. BJOG 2011; 118: 55–61 CrossRef MEDLINE
e43.
Kapadia MZ, Park CK, Beyene J, Giglia L, Maxwell C, McDonald SD: Weight loss instead of weight gain within the guidelines in obese women during pregnancy: a systematic review and meta-analyses of maternal and infant outcomes. PLoS One 2015; 10: e0132650 CrossRef MEDLINE PubMed Central
e44.
Bogaerts A, Ameye L, Martens E, Devlieger R: Weight loss in obese pregnant women and risk for adverse perinatal outcomes. Obstet Gynecol 2015; 125: 566–75 CrossRef MEDLINE
e45.
McBain RD, Dekker GA, Clifton VL, Mol BW, Grzeskowiak LE: Impact of inter-pregnancy BMI change on perinatal outcomes: a retrospective cohort study. Eur J Obstet Gynecol Reprod Biol 2016; 205: 98–104 CrossRef MEDLINE
e46.
O‘Reilly SL, Dunbar JA, Versace V, et al.: Mothers after gestational diabetes in Australia (MAGDA): a randomised controlled trial of a postnatal diabetes prevention program. PLoS Med 2016; 13: e1002092.
e47.
Flynn AC, Dalrymple K, Barr S, et al.: Dietary interventions in overweight and obese pregnant women: a systematic review of the content, delivery, and outcomes of randomized controlled trials. Nutr Rev 2016; 74: 312–28 CrossRef MEDLINE
e48.
Koivusalo SB, Rono K, Klemetti MM, et al.: Gestational diabetes mellitus can be prevented by lifestyle Intervention: The Finnish Gestational Diabetes Prevention Study (RADIEL): a randomized controlled trial. Diabetes Care 2016; 39: 24–30 CrossRef MEDLINE
e49.
Magro-Malosso ER, Saccone G, Di Mascio D, Di Tommaso M, Berghella V: Exercise during pregnancy and risk of preterm birth in overweight and obese women: a systematic review and meta-analysis of randomized controlled trials. Acta Obstet Gynecol Scand 2017; 96: 263–73 CrossRef MEDLINE
e50.
Sagedal LR, Overby NC, Bere E, et al.: Lifestyle intervention to limit gestational weight gain: the Norwegian Fit for Delivery randomised controlled trial. BJOG 2017; 124: 97–109 CrossRef CrossRef
e51.
Sagedal LR, Vistad I, Overby NC, et al.: The effect of a prenatal lifestyle intervention on glucose metabolism: results of the Norwegian Fit for Delivery randomized controlled trial. BMC Pregnancy Childbirth 2017; 17: 167 CrossRef MEDLINE PubMed Central
e52.
Felisbino-Mendes MS, Matozinhos FP, Miranda JJ, Villamor E, Velasquez-Melendez G: Maternal obesity and fetal deaths: results from the Brazilian cross-sectional Demographic Health Survey, 2006. BMC Pregnancy Childbirth 2014; 14: 5 CrossRef MEDLINE PubMed Central
e53.
Garnaes KK, Morkved S, Salvesen O, Moholdt T: Exercise training and weight gain in obese pregnant women: a randomized controlled trial (ETIP trial). PLoS Med 2016; 13: e1002079 CrossRef MEDLINE PubMed Central
e54.
Garnaes KK, Nyrnes SA, Salvesen KA, Salvesen O, Morkved S, Moholdt T: Effect of supervised exercise training during pregnancy on neonatal and maternal outcomes among overweight and obese women. Secondary analyses of the ETIP trial: a randomised controlled trial. PLoS One 2017; 12: e0173937 CrossRef MEDLINE PubMed Central
Department of Gynecology and Obstetrics, Rostock University Medical Center, Rostock, Germany:
PD Dr. med.
Johannes Stubert, Dr. med. Steffi
Hartmann
Department of Gynecology and Obstetrics, Ulm University Medical Center, Ulm, Germany:
PD Dr. med.
Frank Reister, Prof. Dr. med. Wolfgang Janni
Key messages
Risks of maternal diseases in pregnancy in relation to body mass index
Risks of maternal diseases in pregnancy in relation to body mass index
Table 1
Risks of maternal diseases in pregnancy in relation to body mass index
Congenital fetal malformation risks associated with maternal obesity
Congenital fetal malformation risks associated with maternal obesity
Table 2
Congenital fetal malformation risks associated with maternal obesity
Miscarriage risk: fetal and neonatal outcomes in relation to maternal body mass index
Miscarriage risk: fetal and neonatal outcomes in relation to maternal body mass index
Table 3
Miscarriage risk: fetal and neonatal outcomes in relation to maternal body mass index
Obstetric outcome parameters: risk in relation to pre-pregnancy body mass index
Obstetric outcome parameters: risk in relation to pre-pregnancy body mass index
Table 4
Obstetric outcome parameters: risk in relation to pre-pregnancy body mass index
Meta-analyses on the reduction of obesity-associated pregnancy risks (selection
Meta-analyses on the reduction of obesity-associated pregnancy risks (selection
Table 5
Meta-analyses on the reduction of obesity-associated pregnancy risks (selection
Randomized controlled trials on the reduction of obesity-associated pregnancy risks (selection)
Randomized controlled trials on the reduction of obesity-associated pregnancy risks (selection)
eTable
Randomized controlled trials on the reduction of obesity-associated pregnancy risks (selection)
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e1.McKinnon CJ, Hatch EE, Rothman KJ, et al.: Body mass index, physical activity and fecundability in a North American preconception cohort study. Fertil Steril 2016; 106: 451–9 CrossRef MEDLINE
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e8.Bodnar LM, Parks WT, Perkins K, et al.: Maternal prepregnancy obesity and cause-specific stillbirth. Am J Clin Nutr 2015; 102: 858–64 CrossRef MEDLINE PubMed Central
e9.Lindam A, Johansson S, Stephansson O, Wikstrom AK, Cnattingius S: High maternal body mass index in early pregnancy and risks of stillbirth and Infant mortality—a population-based sibling study in Sweden. Am J Epidemiol 2016; 184: 98–105 CrossRef MEDLINE PubMed Central
e10.Carmichael SL, Blumenfeld YJ, Mayo J, et al.: Prepregnancy obesity and risks of stillbirth. PLoS One 2015; 10: e0138549.
e11.Sorbye LM, Klungsoyr K, Samdal O, Owe KM, Morken NH: Pre-pregnant body mass index and recreational physical activity: effects on perinatal mortality in a prospective pregnancy cohort. BJOG 2015; 122: 1322–30 CrossRef MEDLINE PubMed Central
e12.Yao R, Ananth CV, Park BY, Pereira L, Plante LA, Perinatal Research Consortium: Obesity and the risk of stillbirth: a population-based cohort study. Am J Obstet Gynecol 2014; 210: 457 e1–9 CrossRef MEDLINE
e13.Persson M, Johansson S, Villamor E, Cnattingius S: Maternal overweight and obesity and risks of severe birth-asphyxia-related complications in term infants: a population-based cohort study in Sweden. PLoS Med 2014; 11: e1001648 CrossRef MEDLINE PubMed Central
e14.Villamor E, Tedroff K, Peterson M, et al.: Association between maternal body mass index in early pregnancy and Incidence of cerebral palsy. JAMA 2017; 317: 925–36 CrossRef MEDLINE
e15.Shaw GM, Wise PH, Mayo J, et al.: Maternal prepregnancy body mass index and risk of spontaneous preterm birth. Paediatr Perinat Epidemiol 2014; 28: 302–11 CrossRef MEDLINE
e16.Villamor E, Cnattingius S: Interpregnancy weight change and risk of preterm delivery. Obesity (Silver Spring) 2016; 24: 727–34 CrossRef MEDLINE
e17.Sommer C, Sletner L, Morkrid K, Jenum AK, Birkeland KI: Effects of early pregnancy BMI, mid-gestational weight gain, glucose and lipid levels in pregnancy on offspring‘s birth weight and subcutaneous fat: a population-based cohort study. BMC Pregnancy Childbirth 2015; 15: 84 CrossRef MEDLINE PubMed Central
e18.Starling AP, Brinton JT, Glueck DH, et al.: Associations of maternal BMI and gestational weight gain with neonatal adiposity in the Healthy Start study. Am J Clin Nutr 2015; 101: 302–9 CrossRef MEDLINE PubMed Central
e19. Hull HR, Dinger MK, Knehans AW, Thompson DM, Fields DA: Impact of maternal body mass index on neonate birthweight and body composition. Am J Obstet Gynecol 2008; 198: 416. e1–6 CrossRef MEDLINE
e20.Sewell MF, Huston-Presley L, Super DM, Catalano P: Increased neonatal fat mass, not lean body mass, is associated with maternal obesity. Am J Obstet Gynecol 2006; 195: 1100–3 CrossRef MEDLINE
e21.Ehrenberg HM, Mercer BM, Catalano PM: The influence of obesity and diabetes on the prevalence of macrosomia. Am J Obstet Gynecol 2004; 191: 964–8 CrossRef MEDLINE
e22.Harmon KA, Gerard L, Jensen DR, et al.: Continuous glucose profiles in obese and normal-weight pregnant women on a controlled diet: metabolic determinants of fetal growth. Diabetes Care 2011; 34: 2198–204 CrossRef MEDLINE PubMed Central
e23.Friis CM, Qvigstad E, Paasche Roland MC, et al.: Newborn body fat: associations with maternal metabolic state and placental size. PLoS One 2013; 8: e57467.
e24.Jansson T, Powell TL: Placental amino acid transporters. In: Moffett A, Barker DJP, Burton GJ, Thornburg K (eds.): The Placenta and Human Developmental Programming. Cambridge: Cambridge University Press 2010; 147–60.
e25.Wright C, Sibley CP: Placental transfer in health and disease. In: Kay HH, Nelson DM, Wang Y (eds.): The placenta: from development to disease. Oxford, UK: Wiley-Blackwell 2011; p. 66–74 CrossRef MEDLINE
e26.Castillo H, Santos IS, Matijasevich A: Relationship between maternal pre-pregnancy body mass index, gestational weight gain and childhood fatness at 6–7 years by air displacement plethysmography. Matern Child Nutr 2015; 11: 606–17 CrossRef MEDLINE PubMed Central
e27.Woo Baidal JA, Locks LM, Cheng ER, Blake-Lamb TL, Perkins ME, Taveras EM: Risk factors for childhood obesity in the first 1,000 days: a systematic review. Am J Prev Med 2016; 50: 761–79 MEDLINE
e28.Gaillard R, Steegers EA, Duijts L, et al.: Childhood cardiometabolic outcomes of maternal obesity during pregnancy: the Generation R Study. Hypertension 2014; 63: 683–91 CrossRef MEDLINE
e29.Gaillard R, Welten M, Oddy WH, et al.: Associations of maternal prepregnancy body mass index and gestational weight gain with cardio-metabolic risk factors in adolescent offspring: a prospective cohort study. BJOG 2016; 123: 207–16 CrossRef CrossRef
e30.Chu SY, Kim SY, Schmid CH, et al.: Maternal obesity and risk of cesarean delivery: a meta-analysis. Obes Rev 2007; 8: 385–94 CrossRef MEDLINE
e31.Clark-Ganheart CA, Reddy UM, Kominiarek MA, Huang CC, Landy HJ, Grantz KL: Pregnancy outcomes among obese women and their offspring by attempted mode of delivery. Obstet Gynecol 2015; 126: 987–93 CrossRef MEDLINE PubMed Central
e32.Kawakita T, Reddy UM, Landy HJ, Iqbal SN, Huang CC, Grantz KL: Indications for primary cesarean delivery relative to body mass index. Am J Obstet Gynecol 2016; 215: 515 e1–9.
e33.Dresner M, Brocklesby J, Bamber J: Audit of the influence of body mass index on the performance of epidural analgesia in labour and the subsequent mode of delivery. BJOG 2006; 113: 1178–81 CrossRef MEDLINE
e34.ACOG Practice Bulletin No 156: Obesity in pregnancy. Obstet Gynecol 2015; 126: e112–26 CrossRef MEDLINE
e35.Legro RS, Dodson WC, Kunselman AR, et al.: Benefit of delayed fertility therapy with preconception weight loss over immediate therapy in obese women with PCOS. J Clin Endocrinol Metab 2016; 101: 2658–66 CrossRef MEDLINE PubMed Central
e36.van Oers AM, Groen H, Mutsaerts MA, et al.: Effectiveness of lifestyle intervention in subgroups of obese infertile women: a subgroup analysis of a RCT. Hum Reprod 2016; 31: 2704–13 CrossRefMEDLINE
e37.Legro RS: Mr. Fertility Authority, tear down that weight wall! Hum Reprod 2016; 31: 2662–4 CrossRefMEDLINE PubMed Central
e38.Johansson K, Cnattingius S, Naslund I, et al.: Outcomes of pregnancy after bariatric surgery. N Engl J Med 2015; 372: 814–24 CrossRef MEDLINE
e39.Stephansson O, Johansson K, Naslund I, Neovius M: Bariatric surgery and preterm birth. N Engl J Med 2016; 375: 805–6 CrossRef MEDLINE PubMed Central
e40.Caughey AB: Bariatric surgery before pregnancy—is this a solution to a big problem? N Engl J Med 2015; 372: 877–8 CrossRef MEDLINE
e41.Guelinckx I, Devlieger R, Donceel P, et al.: Lifestyle after bariatric surgery: a multicenter, prospective cohort study in pregnant women. Obes Surg 2012; 22: 1456–64 CrossRef MEDLINE
e42.Beyerlein A, Schiessl B, Lack N, von Kries R: Associations of gestational weight loss with birth-related outcome: a retrospective cohort study. BJOG 2011; 118: 55–61 CrossRef MEDLINE
e43.Kapadia MZ, Park CK, Beyene J, Giglia L, Maxwell C, McDonald SD: Weight loss instead of weight gain within the guidelines in obese women during pregnancy: a systematic review and meta-analyses of maternal and infant outcomes. PLoS One 2015; 10: e0132650 CrossRef MEDLINE PubMed Central
e44.Bogaerts A, Ameye L, Martens E, Devlieger R: Weight loss in obese pregnant women and risk for adverse perinatal outcomes. Obstet Gynecol 2015; 125: 566–75 CrossRef MEDLINE
e45.McBain RD, Dekker GA, Clifton VL, Mol BW, Grzeskowiak LE: Impact of inter-pregnancy BMI change on perinatal outcomes: a retrospective cohort study. Eur J Obstet Gynecol Reprod Biol 2016; 205: 98–104 CrossRef MEDLINE
e46.O‘Reilly SL, Dunbar JA, Versace V, et al.: Mothers after gestational diabetes in Australia (MAGDA): a randomised controlled trial of a postnatal diabetes prevention program. PLoS Med 2016; 13: e1002092.
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