Long term alterations of growth after antenatal steroids in preterm twin pregnancies.

OBJECTIVES: To compare the long-term effects of antenatal betamethasone (ANS, ≤16 mg, =24 mg and >24 mg) in twins on infant and childhood growth. METHODS: A retrospective cohort follow up study among 198 twins after ANS including three time points: U1 first neonatal examination after birth and in the neonatal period; U7 examination from the 21st to the 24th month of life and U9 examination from the 60th to the 64th month of life using data from copies of the children's examination booklets. Inclusion criteria are twin pregnancies with preterm labor, cervical shortening, preterm premature rupture of membranes, or vaginal bleeding, and exposure to ANS between 23+5 and 33+6 weeks. Outcome measures are dosage-dependent and sex-specific effects of ANS on growth (body weight, body length, head circumference, body mass index and ponderal index) up to 5.3 years. RESULTS: Overall, 99 live-born twin pairs were included. Negative effects of ANS on fetal growth persisted beyond birth, altered infant and childhood growth, independent of possible confounding factors. Overall weight percentile significantly decreased between infancy and early childhood by 18.8%. Birth weight percentiles significantly changed in a dose dependent and sex specific manner, most obviously in female-female and mixed pairs. The ponderal index significantly decreased up to 42.9%, BMI index increased by up to 33.8%. CONCLUSIONS: ANS results in long-term alterations in infant and childhood growth. Changes between infancy and early childhood in ponderal mass index and BMI, independent of dose or twin pair structure, might indicate an ANS associated increased risk for later life disease. SYNOPSIS: First-time report on long-term ANS administration growth effects in twin pregnancies, showing persisting alterations beyond birth in infant and childhood growth up to 5.3 years as potential indicator of later life disease risk.