Perinatal outcome of singleton siblings born after assisted reproductive technology and spontaneous conception: Danish national sibling-cohort study.
OBJECTIVE
To compare the perinatal outcome of singleton siblings conceived differently.


METHODS
National population-based registry study.


METHODS
Denmark, from 1994 to 2008.


METHODS
Pairs of siblings (13,692 pairs; n = 27,384 children) conceived after IVF, intracytoplasmatic sperm injection (ICSI), frozen embryo replacement (FER), or spontaneous conception subcategorized into five groups according to succession: [1] IVF-ICSI vs. spontaneous conception (n = 7,758), [2] IVF-ICSI vs. FER (n = 716), [3] FER vs. FER (n = 34), [4] IVF-ICSI vs. IVF-ICSI (n = 2,876), and [5] spontaneous conception vs. spontaneous conception (n = 16,000).


METHODS
Observations were obtained from national registries.


METHODS
Birth weight, gestational age, low birth weight (<2,500 g), preterm birth (<37 weeks' gestation) and perinatal deaths.


RESULTS
Mean birth weight was 65 g (95% confidence interval [CI], 41-89] lower in all assisted reproductive technology children compared with their spontaneously conceived siblings. FER children were 167 g (95% CI, 90-244] heavier than siblings born after replacement of fresh embryos. The difference in birth weight between firstborn and second born sibling depended on order of conception method. Higher risk of low birth weight with (odds ratio [OR], 1.4; 95%CI, 1.1-1.7] and preterm birth (OR, 1.3; 95% CI, 1.1-1.6] was observed in IVF/ICSI compared with spontaneous conception.


CONCLUSIONS
When differentiating between order and mode of conception, it seems that assisted reproductive technology plays a role in mean birth weight and risk of low birth weight and preterm birth. Birth weight was higher in siblings born after FER compared with fresh embryos replacement.
Henningsen
Anna-Karina Aaris
AK
Fertility Clinic, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. anna-karina.aaris.henningsen@rh.regionh.dk
Pinborg
Anja
A
Lidegaard
Øjvind
Ø
Vestergaard
Christina
C
Forman
Julie Lyng
JL
Andersen
Anders Nyboe
AN
D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004624:Embryo Transfer / Q000706:statistics & numerical data; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D047928:Premature Birth / Q000401:mortality*; D012042:Registries; D027724:Reproductive Techniques, Assisted / Q000706:statistics & numerical data*; D035781:Siblings; D020554:Sperm Injections, Intracytoplasmic / Q000706:statistics & numerical data; D055815:Young Adult