Maternal birthweight is associated with subsequent risk of vitamin D deficiency in early pregnancy.
BACKGROUND
Maternal low birthweight and vitamin D deficiency in pregnancy are associated with a similar spectrum of adverse pregnancy outcomes including pre-eclampsia and gestational diabetes. However, the relationship between maternal birthweight and subsequent vitamin D concentrations in early pregnancy is largely unknown.


METHODS
We assessed whether self-reported maternal birthweight was associated with risk of early pregnancy vitamin D deficiency (≤20 ng/mL) among a pregnancy cohort (n = 658). Serum 25-hydroxyvitamin D [25(OH)D] was measured using liquid chromatography-tandem mass spectroscopy.


RESULTS
Adjusting for maternal characteristics and month of blood draw, a 100-g higher maternal birthweight was associated with a 5.7% decreased risk of early pregnancy 25(OH)D deficiency [odds ratio (OR) = 0.94; 95% confidence interval (CI) 0.90, 0.99]. Low-birthweight (<2500 g) women were 3.7 times as likely to have early pregnancy 25(OH)D deficiency compared with normal-birthweight women [OR = 3.69; 95% CI 1.63, 8.34]. These relationships were not modified by either pre-pregnancy overweight status [body mass index (BMI) ≥25 kg/m(2)] or adulthood weight trajectory (BMI change ≥2 kg/m(2) from age 18 to pre-pregnancy).


CONCLUSIONS
Further research on shared developmental mechanisms that determine birthweight and vitamin D homeostasis may help identify targets and related preventative measures for adverse pregnancy and birth outcomes.
Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA 98195, USA. jonhuang@uw.edu
Jonathan Y
JY
Huang
Chunfang
C
Qiu
Raymond S
RS
Miller
David S
DS
Siscovick
Michelle A
MA
Williams
Daniel A
DA
Enquobahrie
D000328:Adult; D001724:Birth Weight; D002853:Chromatography, Liquid; D015331:Cohort Studies; D005260:Female; D006801:Humans; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000209:etiology; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012307:Risk Factors; D053719:Tandem Mass Spectrometry; D014481:United States; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications
D014807:Vitamin D; C104450:25-hydroxyvitamin D
birthweight; pregnancy; vitamin D