Serial Third Trimester Abdominal Circumference and Amniotic Fluid Measurements Versus Routine Care

Serial Third Trimester Abdominal Circumference and Amniotic Fluid Measurements Versus Routine Care: A Randomized Controlled Trial (STAR Trial)

The purpose of this study us to compare the rate of prenatal identification of abnormal fetal growth or amniotic fluid between clinical evaluation of uterine size by symphysis fundal height (SFH) measurements versus point-of-care ultrasound (POC-US) evaluation of abdominal circumference (AC) and maximum vertical pocket (MVP).

Inclusion Criteria:

• Maternal age of 18 at the time of consent
• Singleton gestation
• Ultrasound examination that confirms or revises the estimated date of delivery (EDD) before 22 0/7 weeks of gestational age
• Gestational age ≥ 24 weeks gestation

Exclusion Criteria:

• Abnormal aneuploidy screening (1st trimester screening, 2nd trimester screening, integrated screening, NIPT)

• Fetal chromosomal or genetic abnormalities

• Fetal malformations or soft markers identified on fetal anatomy survey

• Current pregnancy is a result of in vitro fertilization

• Documented uterine bleeding after 24 weeks gestation. Unobserved self-reported bleeding with confirmed intact pregnancy on ultrasound after the bleeding episode is not an exclusion criterion.

• Uterine/placental abnormalities including uterine malformations (i.e bicornuate uterus, didelphus uterus), abnormal placentation (placenta previa, accrete, percreta), uterine fibroids.

• Cerclage in the current pregnancy

• History of intrauterine fetal demise

• Fetal isoimmunization or alloimmunization

• History of medical complications such as:

  • Cancer (including melanoma but excluding other skin cancers)
  • Endocrine disease including thyroid disease (recently diagnosed or whose medication dose is not stable), adrenal disease, diabetes mellitus (pregestational and gestational).
  • Renal disease with altered renal function (creatinine > 0.9 or proteinuria)
  • Epilepsy or other seizure disorder
  • Any collagen disease (lupus erythematosus, scleroderma, etc.)
  • Active liver disease (acute hepatitis, chronic active hepatitis, persistently abnormal liver enzymes)
  • Hematological disorder including alloimmune and isoimmune thrombocytopenia but excluding mild iron deficiency anemia (Hb > 9 gm/dl). Patients with sickle cell disease are excluded.
  • Chronic pulmonary disease including asthma requiring regular use of medication and active tuberculosis (TB). An asthma inhaler used on an as needed basis (PRN) for a cold or an asthma attack is not considered regular use.
  • Heart disease except mitral value prolapse not requiring medication
  • Cardiovascular disorders: chronic hypertension
  • Liver disorders accounting for cholestasis
  • Infectious diseases: HIV, Cytomegalovirus (CMV), toxoplasmosis, parvovirus B19