Fetal Growth versus Birthweight: The Role of Placenta versus Other Determinants

Abstract

IntroductionBirthweight is used as an indicator of intrauterine growth, and determinants of birthweight are widely studied. Less is known about determinants of deviating patterns of growth in utero. We aimed to study the effects of maternal characteristics on both birthweight and fetal growth in third trimester and introduce placental weight as a possible determinant of both birthweight and fetal growth in third trimester.MethodsThe STORK study is a prospective cohort study including 1031 healthy pregnant women of Scandinavian heritage with singleton pregnancies. Maternal determinants (age, parity, body mass index (BMI), gestational weight gain and fasting plasma glucose) of birthweight and fetal growth estimated by biometric ultrasound measures were explored by linear regression models. Two models were fitted, one with only maternal characteristics and one which included placental weight.ResultsPlacental weight was a significant determinant of birthweight. Parity, BMI, weight gain and fasting glucose remained significant when adjusted for placental weight. Introducing placental weight as a covariate reduced the effect estimate of the other variables in the model by 62% for BMI, 40% for weight gain, 33% for glucose and 22% for parity. Determinants of fetal growth were parity, BMI and weight gain, but not fasting glucose. Placental weight was significant as an independent variable. Parity, BMI and weight gain remained significant when adjusted for placental weight. Introducing placental weight reduced the effect of BMI on fetal growth by 23%, weight gain by 14% and parity by 17%.ConclusionIn conclusion, we find that placental weight is an important determinant of both birthweight and fetal growth. Our findings indicate that placental weight markedly modifies the effect of maternal determinants of both birthweight and fetal growth. The differential effect of third trimester glucose on birthweight and growth parameters illustrates that birthweight and fetal growth are not identical entities.

Role of Insulin in Placental Transport of Nutrients in Gestational Diabetes Mellitus

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β-cell dysfunction in women with previous gestational diabetes is associated with visceral adipose tissue distribution

“…Exclusion criteria were multiple pregnancies, known pre-gestational diabetes and severe chronic diseases (lung, cardiac, gastrointestinal or renal), and pregnancies with fetal malformations discovered at the routine scan in week 18 of pregnancy. Details about the study have been published (13). The follow-up study was performed 5 years after the index pregnancy and 300 women participated (Fig.…”

Placental 5-methylcytosine and 5-hydroxymethylcytosine patterns associate with size at birth

“…1 The factors that determine size at birth are complex but include differences in placental size and function. 2 Imprinted genes, which are preferentially expressed from one parental allele only, are of particular importance in determining normal placental growth and transfer capacity, notably transport of the nutrients essential for normal fetal growth. 3 Evidence from mouse models and humans suggests that genes that are paternally expressed tend to increase fetal growth, whereas maternally expressed genes restrict fetal growth.…”