Last reviewed: August 2019
Last updated: April  2019



History and exam

Key diagnostic factors

  • maternal last menstrual period (LMP)
  • distance from the maternal superior pubis to the uterine fundus
  • infant physical maturity score
  • infant neuromuscular maturity score
  • combined physical/neuromuscular score <10: gestational age <28 weeks
  • combined physical/neuromuscular score 11 to 19: gestational age 29 to 31 weeks
  • combined physical/neuromuscular score 20 to 24: gestational age 32 to 33 weeks
  • combined physical/neuromuscular score 25 to 33: gestational age 34 to 36 weeks

Other diagnostic factors

  • infant birth weight (appropriate for gestational age infants, AGA)

Risk factors

  • spontaneous preterm labor
  • intrauterine infection
  • preterm premature rupture of membranes (PPROM)
  • pre-eclampsia/pregnancy-induced hypertension
  • abruption/antepartum hemorrhage
  • abnormal amniotic fluid volume
  • severe bacterial vaginosis
  • multiple gestation
  • previous preterm birth
  • fetal abnormality
  • cervical incompetence/uterine abnormality
  • gestational diabetes
  • maternal surgery during pregnancy
  • chronic maternal illness
  • short interpregnancy time interval
  • drug use (tobacco, cocaine, heroin)
  • maternal pregnancy body mass index <19 or >35
  • stress/depression
  • nonwhite race

Diagnostic investigations

1st investigations to order

  • fetal biometry during prenatal period
Full details

Treatment algorithm


Authors VIEW ALL

Associate Professor

Section of Neonatology and Department of Pediatrics

Baylor College of Medicine




MP declares that he has no competing interests.

Dr Mohan Pammi would like to gratefully acknowledge Dr Stephen Welty and Dr James L. Wynn, previous contributors to this monograph. SW and JLW declare that they have no competing interests.

Peer reviewers VIEW ALL

Consultant Obstetrician and Gynaecologist

Gloucestershire Royal Hospital




IB declares that he has no competing interests.

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