Clinical Research Directory

Inclusion Criteria: * Maternal age ≥ 18 years and ability to give informed consent. * Singleton gestation * Ultrasound examination that confirms or revises the EDD before 14 weeks of gestational age * Gestational age ≥ 35 weeks' gestation * Normal aneuploidy screening (1st trimester screening, 2nd trimester screening, integrated screening, NIPT) when performed * Spontaneously conceived pregnancy (i.e the current pregnancy is not the result of in vitro fertilization) Exclusion Criteria: * Fetal chromosomal or genetic abnormalities if invasive prenatal diagnosis is performed * Fetal malformations or soft markers identified on fetal anatomy survey * Episodes of uterine bleeding after 24 weeks gestation. Unobserved self-reported bleeding with confirmed intact pregnancy on ultrasound after the bleeding episode is not an exclusion criteria. * Uterine/placental abnormalities including uterine malformations (i.e bicornuate uterus, didelpus uterus), abnormal placentation (placenta previa, accreta, percreta), uterine fibroids. * Cerclage in the current pregnancy * History of intrauterine fetal demise * History of fetal growth restriction or birth weight \> 4Kg in a previous pregnancy * Fetal isoimmunization or alloimmunization * Fetal demise in previous pregnancies * Cancer (including melanoma but excluding other skin cancers). Dysplastic or pre-neoplatic conditions such as cervical intraepithelial neoplasia are admissible. * 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, proteinuria \> 300 mg/24 hour) * Epilepsy or other seizure disorder * Any collagen disease (lupus erythematosus, scleroderma, etc.) * Active liver disease (acute hepatitis, chronic active hepatitis, persistently abnormal liver enzymes). Liver disorders accounting for cholestasis (including cholestasis of pregnancy) if diagnosed prior to enrollment. * 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 TB. An asthma inhaler used on an as needed basis 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, gestational hypertension or preeclampsia diagnosed prior to enrollment * Infectious diseases: HIV, CMV, toxoplasmosis, parvovirus B19, HBV, HCV * Chronic treatments with medications such as aspirin, steroids, anti-hypertensive agents, immunosuppressants, antineoplastic drugs. * Prior laparoscopic or open uterine surgeries where the uterine cavity was entered (such as myomectomies) * Resectoscopic myomectomies (prior resectoscopic polypectomies are not contraindications) * Prior classical cesarean deliveries.