Gestational weight gain and adverse pregnancy outcomes in a nulliparous cohort

https://doi.org/10.1016/j.ejogrb.2012.11.020Get rights and content

Abstract

Objective

Excessive gestational weight gain (GWG) is an important contributing factor to the obesity epidemic in women and is associated with pregnancy complications. We investigated the relationship between GWG and caesarean delivery in labour, large for gestational age (LGA), small for gestational age (SGA) infants and pregnancy-induced hypertension by maternal pre-pregnancy body mass index (BMI) in a contemporary nulliparous cohort.

Study design

Using 2009 Institute of Medicine guidelines, participants in the SCOPE study (from Cork, Ireland, Auckland, New Zealand and Adelaide, Australia) were classified into GWG categories (low, normal and high) according to pre-pregnancy BMI. Maternal characteristics and pregnancy outcomes were compared between weight gain categories. SGA and LGA were defined as <10th and >90th customised birthweight centile. Multivariable analysis adjusted for confounding factors that impact on GWG including BMI.

Results

Of 1950 participants, 17.2% (n = 335) achieved the recommended GWG, 8.6% (n = 167) had low and 74.3% (n = 1448) had high GWG. Women with high GWG had increased rates of LGA infants [adjusted OR 4.45 (95% CI 2.49–7.99)] and caesarean delivery in labour [aOR 1.46 (1.03–2.07)]. SGA was increased in women with low GWG [aOR 1.79 (1.06–3.00)].

Conclusion

Three quarters of participants had high GWG, which was associated with an independent risk of LGA infants and caesarean in labour. Low GWG was associated with SGA infants. These adverse outcomes are potentially modifiable by achievement of normal GWG, which should be an important focus of antenatal care.

Introduction

The global obesity epidemic affecting women of reproductive age is a major contributor to adverse pregnancy outcomes [1], [2]. Excessive gestational weight gain (GWG) is reported to be a contributing factor to this obesity epidemic in women [1], [2], [3], [4], [5]. Furthermore, excessive GWG has been associated with increased rates of pregnancy complications [3], [4], [6], [7], [8], [9], [10], [11] including large for gestational age (LGA) infants [3], [4], [7], [8], [10], [12], [13], increased non-elective caesarean delivery [3], [4], [10], [12], [14], preeclampsia and gestational hypertension [3], [15]. Conversely, limiting GWG, especially in obese women, has been associated with improved pregnancy outcomes [9], [10], [12]. Inadequate GWG, on the other hand, may increase the risk of small for gestational age (SGA) infants [3], [4], [7], [8], [10], [12], [13], [16], [17]. Some of these previous studies have been retrospective [10], [11], [13], [16], [18], have used self-reported maternal height and weight [3], [7], [10], [12], [13], [18] and not adjusted GWG for gestation at delivery [7], [9], [10].

The Institute of Medicine (IOM) guidelines on GWG were developed in 1990 (prior to the obesity epidemic) to optimise birthweight and to prevent “premature births and SGA infants” [1], [5]. The guidelines were revised in 2009 to match the “dramatic shifts in the demographic and epidemiologic profile” in “U.S. women of childbearing age” [5]. At this time several publications had highlighted the relationship between excessive GWG and pregnancy complications, especially among obese women [3], [4], [5], [6], [19]. The updated guidelines reduced the recommended weight gain for obese women and increased recommended GWG ranges for underweight women [5].

Currently there are no published data regarding GWG groups and the impact of GWG on pregnancy outcome in New Zealand or Ireland and no Australian data apart from a study from a birth cohort in the 1980s [14]. The aims of this study, in participants from the Screening for Pregnancy Endpoints (SCOPE) study, were to (1) report GWG gain categories in a contemporary nulliparous cohort and (2) establish the independent relationship between GWG and rates of caesarean delivery in labour, SGA, LGA and pregnancy-induced hypertension.

Section snippets

Study design and ethics approval

The participants were healthy, nulliparous women with singleton pregnancies recruited to the SCOPE study between November 2004 and February 2011, in Cork, Ireland, Auckland, New Zealand, and Adelaide, Australia. The SCOPE study is a prospective, multicentre international screening study which aims to develop screening tests to predict preeclampsia, SGA infants and spontaneous preterm birth. Ethics approval was obtained from local ethics committees (New Zealand AKX/02/00/364, Australia REC

Results

Of the 5026 women recruited to the SCOPE study in the three participating centres 1950 were eligible for this study – 1211 from Cork, 264 from Auckland and 475 from Adelaide (Fig. 1). In the whole cohort, 55% (n = 1074) of women were of normal weight, 29% (n = 566) were overweight and 16% (n = 310) were obese. High GWG was observed in 67% (n = 724) of normal weight women, 84% (n = 476) of overweight women and 80% (n = 248) of obese women. The first and last recorded weights used to calculate gestational

Comment

Disturbingly, we found that the large majority (74.3%) of healthy nulliparous participants in this study had excessive GWG. Of further concern, and consistent with previous publications [5], [19], we also report that overweight and obese women were the most likely to have high GWG, with mean estimated GWGs of 13.77 ± 5.2 kg for overweight and 11.92 ± 8.1 kg for obese women compared with the recommended IOM optimum GWGs of 7–11 kg and 5–9 kg respectively [5]. These findings are important, as excessive

Conclusion

Approximately three-quarters of healthy nulliparous women in our study had high GWG. High GWG was associated with independent risks of caesarean in labour and LGA infants. Low GWG was associated with elevated risk of SGA infants. These adverse outcomes are potentially modifiable by achievement of normal GWG, which should be an important focus of antenatal care.

Funding

Funding for the study was received from:

New Zealand: New Enterprise Research Fund, Foundation Research Science and Technology; Health Research Council; Evelyn Bond Fund, National Women's, Auckland City Hospital; Mercia Barnes Trust, Royal Australasian and New Zealand College of Obstetricians and Gynaecologists. Australia: Premier's Science and Research Fund, South Australian Government. Ireland: Health Research Board.

Conflicts of interest

No conflict of interest disclosed.

Clinical trial registration

Australian New Zealand Clinical Trials Registry, www.anzctr.org.au, ACTRN12607000551493.

Acknowledgements

We would like to thank the pregnant women who participated in the SCOPE study, Eliza Chan for statistical assistance, Associate Professor Claire Roberts for her contributions in establishing the SCOPE study in Adelaide, Denise Healy for coordinating the Australian SCOPE study, Nicolai Murphy for coordinating the Cork SCOPE study and the SCOPE research midwives.

References (32)

  • A. Beyerlein et al.

    Within-population average ranges compared with Institute of Medicine recommendations for gestational weight gain

    Obstet Gynecol

    (2010)
  • M. Blomberg

    Maternal and neonatal outcomes among obese women with weight gain below the new Institute of Medicine recommendations

    Obstet Gynecol

    (2011)
  • D.E. Durie et al.

    Effect of second-trimester and third-trimester rate of gestational weight gain on maternal and neonatal outcomes

    Obstet Gynecol

    (2011)
  • S. Park et al.

    Assessment of the Institute of Medicine recommendations for weight gain during pregnancy: Florida, 2004–2007

    Matern Child Health J

    (2011)
  • N.E. Stotland et al.

    Gestational weight gain and adverse neonatal outcome among term infants

    Obstet Gynecol

    (2006)
  • A.A. Mamun et al.

    Associations of maternal pre-pregnancy obesity and excess pregnancy weight gains with adverse pregnancy outcomes and length of hospital stay

    BMC Pregnancy Childbirth

    (2011)
  • Cited by (0)

    1

    On behalf of the SCOPE Consortium.

    View full text