Outcomes of fetuses with small head circumference on second-trimester ultrasonography.
OBJECTIVE
We examined the outcomes of pregnancies in which the fetal head circumference (HC) was below the 5(th) centile at the routine second-trimester scan.


METHODS
We retrospectively analysed outcomes of 18,377 women according to HC Z scores at second-trimester ultrasound examination between 2001 and 2008. We collected all major malformations, intrauterine deaths and other abnormal outcomes.


RESULTS
Six hundred seventy-four fetuses (3.7%) had an HC below the 5(th) centile. Twenty-one major malformations were noted, consisting mainly of neurological abnormalities (3.1%). There were seven intra uterine fetal death (1.3%). Of all the fetuses, 26% were lost to follow-up. Outcome and neurological development was normal in 467 cases, based on neonatal examination and/or parent or general practitioner reports. Major abnormalities were noted in respectively 26.2%, 3.0% and 1.1% of fetuses with Z scores < -2.5, -2.5 to -2.0, and -2 to -1.645, compared with 0.3% of fetuses with normal HC (p < 10(-4)).


CONCLUSIONS
A head circumference below the 5(th) centile at second-trimester scan is associated with various abnormalities, especially neurological disorders. The outcome was worse when the HC was smaller. An HC Z score below -2.5 was strongly associated with neurological and chromosomal abnormalities. Conversely, an HC Z score below -1.645 but above -2, excluding cases with prenatally diagnosed malformations, seems to be reassuring for favorable neonatal outcome.
Department of Obstetrics and Gynecology, Faculté de médecine, Université Paris Descartes, Sorbonne Paris Cite, Assistance Publique-Hôpitaux de Paris, Hôpital Necker Enfants Malades, 149 rue de Sèvres, 75015, Paris, France.
Benjamin
B
Deloison
Gihad E
GE
Chalouhi
Jean-Pierre
JP
Bernard
Yves
Y
Ville
Laurent J
LJ
Salomon
D005260:Female; D005317:Fetal Growth Retardation / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005333:Fetus / Q000033:anatomy & histology; D005865:Gestational Age; D006257:Head / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000196:embryology; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D009421:Nervous System Malformations / Q000000981:diagnostic imaging / Q000196:embryology / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D011256:Pregnancy Outcome / Q000453:epidemiology*; D011262:Pregnancy Trimester, Second; D012107:Research Design; D012189:Retrospective Studies; D012985:Software Design; D016216:Ultrasonography, Prenatal / Q000706:statistics & numerical data