Folic acid supplementation, preconception body mass index, and preterm delivery: findings from the preconception cohort data in a Chinese rural population

Abstract

BackgroundFolic acid (FA) supplementation before and during the first trimester can reduce the risk of occurrence of preterm delivery (PTD). Preconception body mass index (BMI) is also associated with PTD. This study aimed to investigate the combined effect of FA supplements and preconception BMI on the risk of PTD.MethodsThe data of a cohort from 2010–2011 that was obtained through a preconception care service in China was used (including 172,206 women). A multivariable regression model was used to investigate the association between maternal preconception conditions and the risk of PTD. The interaction of preconception BMI and FA supplementation was measured by a logistic regression model.ResultsTaking FA supplements in the preconception period or in the first trimester reduced the risk of PTD (odds ratio [OR] = 0.58 and OR = 0.61, respectively). Women with an abnormal BMI had an increased risk of PTD (OR = 1.09, OR = 1.10, and OR = 1.17 for underweight, overweight, and obese, respectively). Preconception BMI showed an interaction with the protective effect of FA supplementation for PTD. With regard to the interaction of FA supplementation, the adjusted odds ratio (aOR) was 0.57 (95 % CI: 0.51, 0.64) in underweight women, 0.85 (95 % CI: 0.73, 0.98) in overweight women, and 0.77 (95 % CI, 0.65, 0.91) in obese women. Preconception BMI also showed an interaction with the time of FA supplementation. Women with a normal BMI who began to take FA supplements in the preconception period had the lowest risk of PTD (aORs: 0.58 vs. 0.65 beginning in the first trimester). The aORs at preconception and the first trimester in the underweight group were 0.56 vs. 0.60. The aORs at preconception and the first trimester were 0.94 vs. 0.65 and 1.15 vs. 0.60 in the overweight and obesity groups, respectively.ConclusionsIn our study, FA supplements reduced the risk of PTD, while abnormal BMI raised the risk of PTD, although higher BMI categories did not have this higher risk once adjusted analysis was conducted. The protective effect of FA supplementation for PTD was reduced in women with overweight or obesity. To get better protection of FA supplementation, women with normal BMI or underweight should begin to use in preconception, while women with overweight or obesity should begin to use after conception.

Preconception TSH and pregnancy outcomes: a population‐based cohort study in 184 611 women

“…More details about NPCP were described in Wang et al's study. 19 From 2010 to 2012, a total of 248 501 volunteer couples and their children were recruited in 220 pilot counties in 30 provinces in mainland China. The total population of 30 research provinces in 2012 was 1Á3 billion (females, 650 million; males, 680 million).…”

The influence of age at menarche, menstrual cycle length and bleeding duration on time to pregnancy: a large prospective cohort study among rural Chinese women

“…Through to December 2013, the survey had been conducted in this province with nearly 1.5 million couples in 234 counties. Details of the program have been described elsewhere . In this study, nulliparous women planning to conceive and at a normal reproductive age (20–49 years old) were enrolled.…”

“…In addition, any pregnancy history, menstrual characteristics and lifestyle patterns were also collected for all participants. Physical and biochemical examinations were also carried out by medical staff at the same time, including measurement of maternal height and weight, blood pressure, and haemoglobin levels . Trained nurses conducted follow‐up interviews.…”

<p>Micronutrients Deficiency and Their Associations with Pregnancy Outcomes: A Review</p>

“…39,40 Also, obese pregnant women were at a higher risk of MN deficiencies due to poor eating habits and reliance on energy-dense and MN-deprived foods 41 leading to pre-eclampsia and DM which resulted in PTD. 42 Intrauterine MN status also has links with the potential risk of chronic diseases although the root causes were largely unknown. 43 Different studies have been conducted on the effect of MMN versus IFA on pregnancy outcomes taking into consideration common adverse outcomes like LBW, SGA, PTD, weight, stillbirth, perinatal, neonatal or infant mortality.…”