European Journal of Cardiovascular Medicine

The prevalence of overweight and obesity is increasing among women of childbearing age. An estimated 12% of  pregnant women 18–49 years of age in the India are considered overweight (body mass index _BMI_25–29.9 kg/m2). Observational studies show that obese women have up to a 2-fold increased risk for a cesarean delivery compared with normal-weight women^2-9.  However, it is unclear what factors may contribute to this elevated risk, because scientific evidence on the effect of maternal pre pregnancy weight status on labor progression is still limited^8,10 . Does the course of labor tend to differ for overweight and obese women, compared with that of normal-weight women? The purpose of this study was to examine the effect of maternal overweight and obesity on the pattern of labor progression in pregnant women with a singleton, term pregnancy with spontaneous onset labour.

This was a prospecve observaonal study conducted from August 2017 to July 2018. The study was conducted at Department of Obstetrics and Gynaecology, SS Medical College Rewa. The study was approved by Instuonal Ethics Commiee. All paents admied in the labour room during the course of study and fulfilling the inclusion and exclusion criteria were enrolled in the study. After  considering inclusion and exclusion criteria all laboring females were allowed to progress naturally and a four hourly partogram was recorded. All females who required augmentaon, caesarean or instrumental delivery were excluded from the study. On the basis of individual labour progress chart which were obtained, a final composite labour graph was derived and appropriate statistical tests were applied.

Inclusion criteria:

1. Term pregnant female of Indian origin
2. Maternal age: 18-35 years old
3. Gestaonal age: 37 weeks to 41 weeks
4. Spontaneous onset of labour
5. First to fourth gravida with singleton pregnancy with vertex presentaon
6. Cervical dilataon less than or equal to 4cm
7. Normal neonatal outcome

 Exclusion criteria:

1. Induced labour, Elecve LSCS or emergency LSCS
2. With history of any medical illness
3. High risk pregnancy
4. Oxytocin augmented labour

 Figure 1 depicts the process of selection of final study population

Prepregnancy weight was obtained from medical records and based on maternal self-report. Maternal height was measured and recorded at the first prenatal visit or obtained later during medical record abstraction. Maternal age is

defined as age in completed years at the time of recruitment

Table 1 presents baseline sociodemographic, anthropometric  characteristics of the overall study population,stratified by maternal prepregnancy BMI. Overweight women were similar to normal-weight women on most factors, but obese women had a significantly greater proportion in the younger age categories.

             Table 1   BMI AND CHARACTERISTICS OF STUDY POPULATION

 Table 2 - ASSOCIATION OF BMI WITH RATE OF CERVICAL DILATATION IN  cm/hr

Table 2 presents association of BMI with rate of cervical dilatation. We have found that BMI is directly related to rate of cervical dilataon. Mean rate of cervical dilataon was 1.46 cm/hr in group with BMI< 18.5 .Mean rate of cervical dilatation was 1.40 cm/hr for pregnant women with normal BMI but it was  <0.9 cm/hr for obese women .Ironically  mean rate of cervical dilatation was 1.38 cm/hr  ,faster than normal BMI women for over weight women .

 ASSOCIATION OF CERVICAL DILATATION WITH BMI OF STUDY POPULATION

Obese women had a significantly longer median duration of labor from 4 to 10 cm compared with normal-weight women. Upon further examination, the longer median duration of labor in obese women showed more slower labor progression from 4 to 6 cm. After 6 cm labour progression was slow than in normal BMI pregnant women but was relatively less slower than before 6 cm dilatation. No significant differences were seen between normal and overweight women in the active phase of labor.

                   Table 3 - ASSOCIATION CERVICAL DILATATION WITH BMI OF STUDY POPULATION

Previous studies on pregnancy outcomes in obese women have reported briefly on the prevalence of select characteristics of labor and delivery^8,10,11,12 or offered a crude estimate of the duration of labor¹³. However, few have explored in depth the effect of maternal overweight and obesity on labor progression after adjusting for potential confounders in current obstetric practice. The results from this study are consistent with those from previous studies that showed that obese women are more likely to have an inadequate contraction pattern during the first stage of labor8 and to have slower labour progression ^8,10,12 compared with nonobese women.  labor progression before 6 cm of cervical dilation was significantly slower in obese women compared with normal-weight women, Several authors have speculated that this phenomenon may be due to the added soft-tissue deposits in the pelvis of obese women, which coupled with a larger fetus might necessitate more time and slower labour progressionlabor^5,8,13. Studies that have measured suprailiac skinfold thickness confirm perceptions that more maternal fat is accumulated centrally than peripherally during pregnancy^14,15 especially among obese women¹⁶ .Thus, it is possible that added soft-tissue deposits in the maternal pelvis might narrow the diameter of the birth canal and prolong labor. However, direct evidence of fat deposition in the pelvis of overweight and obese women is needed to support this assertion and is beyond the scope of this analysis.

 Majority of our study populaon have BMI< 24.9 . Anjel vahratianh¹⁷ also concluded in his study that labour progression in over weight and obese women was slower than that of normal BMI pregnant women before 6 cm cervical dilatation . Oladepo et al¹⁸ also found that the time difference to reach 10 cm cervical dilatation was 1.2 hr from lowest BMI 9<25) to highest BMI (>40) for nulliparous women. He also concluded that labour proceeds more slowly as BMI increases, suggesting that labour management be altered to allow longer ti me for these differences.

The findings of this study must be interpreted with recognition of its limitations. First, the measurement of cervical dilation was subjective. Continuous monitoring of cervical dilation was not performed and the measurements were based on vaginal examinations performed by several obstetricians 4 hourly . Second pre pregnancy weight was taken on the basis of recall by pregnant females or by weight at first antenatal visit from medical records .

Few studies to date have examined the characteristics of labor and delivery for overweight and obese women. In contrast, this study abstracted detailed intrapartum data to examine the relationship between maternal prepregnancy weight status and the pattern of labor progression in term, low risk women with spontaneous onset labour. In our study, obese women had a significantly slower labor from 4 to 10 cm, compared with that of normal-weight women. In particular, the pattern of labor progression for obese women was significantly slower than that of normal-weight women before 7 cm. Given that nearly 25% of women of childbearing age are either overweight or obese as per NFHS -5 survey , it is critical to consider differences in labor progression by maternal prepregnancy BMI before additional interventions are performed.

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