[Effects of pre-pregnancy body mass index on pregnancy outcomes].
OBJECTIVE
To explore the effects of pre-pregnancy body mass index (BMI) upon adverse pregnancy outcomes.


METHODS
We selected a population-based cohort of 48 867 nulliparous women in mainland China with singleton and full-term deliveries in 2011. The cohort was categorized in accordance with pre-pregnancy BMI as follows: underweight <18.5; normal weight = 18.5-23.9; overweight = 24-27.9; obesity ≥ 28. Logistic regression was used to estimate the association between BMI and adverse maternal, peripartum and perinatal outcomes with normal weight as a reference range.


RESULTS
(1) Overweight and obese women were more likely to have hypertensive disorders with odds ratios of 2.29 and 6.02, gestational diabetes mellitus 2.27, 4.99; (2)the odds ratios for fetal macrosomia increased among women with higher BMI as follows: 0.59, 1.99 and 3.15, whereas only lean women had significantly increased risk of delivering babies with low birth weight (LBW) 1.62; (3)increased BMI was associated with reduced rates of assisted vaginal delivery and increased rates of caesarean section.


CONCLUSIONS
As an independent risk factor for adverse maternal and fetal outcomes, pre-pregnancy obesity should be managed properly.
Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China.
Chunming
C
Li
Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China. Email: zhangwy9921@hotmail.com.
Weiyuan
W
Zhang
D000328:Adult; D015992:Body Mass Index; D005260:Female; D005315:Fetal Diseases / Q000453:epidemiology*; D006801:Humans; D009765:Obesity / Q000453:epidemiology; D050177:Overweight / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011256:Pregnancy Outcome; D012307:Risk Factors; D055815:Young Adult