Prevalence, risk factors and outcomes of velamentous and marginal cord insertions: a population-based study of 634,741 pregnancies.
OBJECTIVE
To determine the prevalence of, and risk factors for anomalous insertions of the umbilical cord, and the risk for adverse outcomes of these pregnancies.


METHODS
Population-based registry study.


METHODS
Medical Birth Registry of Norway 1999-2009.


METHODS
All births (gestational age >16 weeks to <45 weeks) in Norway (623,478 singletons and 11,263 pairs of twins).


METHODS
Descriptive statistics and odds ratios (ORs) for risk factors and adverse outcomes based on logistic regressions adjusted for confounders.


METHODS
Velamentous or marginal cord insertion. Abruption of the placenta, placenta praevia, pre-eclampsia, preterm birth, operative delivery, low Apgar score, transferral to neonatal intensive care unit (NICU), malformations, birthweight, and perinatal death.


RESULTS
The prevalence of abnormal cord insertion was 7.8% (1.5% velamentous, 6.3% marginal) in singleton pregnancies and 16.9% (6% velamentous, 10.9% marginal) in twins. The two conditions shared risk factors; twin gestation and pregnancies conceived with the aid of assisted reproductive technology were the most important, while bleeding in pregnancy, advanced maternal age, maternal chronic disease, female foetus and previous pregnancy with anomalous cord insertion were other risk factors. Velamentous and marginal insertion was associated with an increased risk of adverse outcomes such as placenta praevia (OR = 3.7, (95% CI = 3.1-4.6)), and placental abruption (OR = 2.6, (95% CI = 2.1-3.2)). The risk of pre-eclampsia, preterm birth and delivery by acute caesarean was doubled, as was the risk of low Apgar score, transferral to NICU, low birthweight and malformations. For velamentous insertion the risk of perinatal death at term was tripled, OR = 3.3 (95% CI = 2.5-4.3).


CONCLUSIONS
The prevalence of velamentous and marginal insertions of the umbilical cord was 7.8% in singletons and 16.9% in twin gestations, with marginal insertion being more common than velamentous. The conditions were associated with common risk factors and an increased risk of adverse perinatal outcomes; these risks were greater for velamentous than for marginal insertion.
Department of Obstetrics and Gynaecology, Haukeland University Hospital, Bergen, Norway. cathrine.ebbing@molmed.uib.no
Cathrine
C
Ebbing
Torvid
T
Kiserud
Synnøve Lian
SL
Johnsen
Susanne
S
Albrechtsen
Svein
S
Rasmussen
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D016017:Odds Ratio; D063868:Patient Outcome Assessment; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000209:etiology*; D011256:Pregnancy Outcome; D015995:Prevalence; D062486:Public Health Surveillance; D012042:Registries; D012307:Risk Factors; D014470:Umbilical Cord / Q000002:abnormalities*; D055815:Young Adult