Pregnancy Complications

The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The fallopian tubes receive an ovum after ovulation and help move it and/or a fertilized embryo toward the uterus via ciliated cells lining the tubes and peristaltic movements of its smooth muscle. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. The transition point is known as the squamocolumnar junction, which is the site of most cervical cancers. These organs are supplied by the uterine and ovarian arteries and innervated by the autonomic nervous system.

Spontaneous abortion, also known as miscarriage, is the loss of a pregnancy before 20 weeks' gestation. However, the layperson use of the term “abortion” is often intended to refer to induced termination of a pregnancy, whereas “miscarriage” is preferred for spontaneous loss. Most spontaneous abortions occur within the 1st 12 weeks of gestation and can be caused by several factors such as infection, trauma, and genetic and autoimmune causes. There are different types of spontaneous abortions, including threatened, inevitable, incomplete, complete, and missed abortions. Spontaneous abortions are diagnosed based on history, physical examination, and ultrasound findings. Management options include expectant, medical, or surgical therapy.

Gestational trophoblastic diseases are a spectrum of placental disorders resulting from abnormal placental trophoblastic growth. These disorders range from benign molar pregnancies (complete and partial moles) to neoplastic conditions such as invasive moles and choriocarcinoma. Diagnosis is confirmed by elevated serum beta human chorionic gonadotropin (hCG) and ultrasound findings, which are dependent on the disorder. Treatment is primarily through dilation and curettage and/or methotrexate.

Chorioamnionitis, commonly referred to as intraamniotic infection (IAI), is a common obstetric complication involving infection and inflammation of the fetal membranes, amniotic fluid, placenta, or the fetus itself. Chorioamnionitis is typically caused by a polymicrobial infection that ascends from the lower genitourinary tract. Primary risk factors include prolonged rupture of membranes and prolonged labor. Chorioamnionitis is diagnosed by clinical findings, including maternal fever. Chorioamnionitis is managed with antibiotics, and by ensuring continued labor progress (or initiating progress) toward delivery. Chorioamnionitis typically resolves soon after delivery. Significant maternal and fetal complications are possible, warranting prompt diagnosis and treatment.

Antepartum hemorrhage is defined as vaginal bleeding that occurs after 20 weeks of gestation and is unrelated to labor. The most important causes are placental abruption (most common), placenta previa (2nd most common), vasa previa, and uterine rupture. Placental abruption and uterine rupture are diagnosed clinically. Placenta previa and vasa previa are usually diagnosed as part of routine screening on a midtrimester ultrasound, and digital exams in these women must be avoided. All of these conditions can lead to maternal and/or fetal hemorrhage, necessitating emergency C-section and maternal and/or fetal resuscitation.

Normal placental structure and function are essential for a healthy pregnancy. Some of the most common placental abnormalities include structural anomalies (such as a succenturiate lobe or velamentous cord insertion), implantation anomalies (such as placenta accreta and placenta previa), and functional anomalies (such as placental insufficiency). The placenta is typically seen well on ultrasound, and placental assessment is part of routine antenatal screening, which is when most structural and implantation anomalies are identified. Because of the extensive maternal and fetal circulation through the placenta, placental abnormalities can significantly increase the risk of serious antepartum or postpartum hemorrhage. Placental abnormalities also frequently impact decisions regarding the timing and route of delivery.

During pregnancy, fetal development and growth are sustained completely by the mother until birth. The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. The placenta is also called “the fetal lung” because it allows for gas exchange between the maternal and fetal circulation. Diseases or defects in the placenta often have severe, and even fatal, complications.

Hypertensive disorders of pregnancy include chronic hypertension, preeclampsia/eclampsia, gestational hypertension, and hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. These syndromes pose a significant risk to the pregnant woman and her fetus. Hypertension is defined as a BP > 140/90 mm Hg and can be diagnosed before (chronic) or after (gestational) the 20th week of gestation. Preeclampsia is gestational hypertension with proteinuria or end-organ damage. Eclampsia is preeclampsia with seizures. HELLP syndrome is a severe manifestation of preeclampsia leading to hemolysis, low platelets, and liver injury. Management is with antihypertensives and magnesium sulfate for seizure prophylaxis. The definitive treatment for all hypertensive disorders of pregnancy is delivery.

Ectopic pregnancy refers to the implantation of a fertilized egg (embryo) outside the uterine cavity. The main cause is disruption of the normal anatomy of the fallopian tube. Consequently, affected patients may suffer from acute abdominal pain as the developing embryo increases in size. Ectopic pregnancy can be quickly diagnosed by means of an ultrasound and laboratory analysis. Management can be expectant, medical, or surgical. Severe cases involving rupture of the fallopian tube and hemorrhage are considered a medical emergency and require immediate surgery.