Abdominal pain during pregnancy presents unique clinical challenges, and the differential diagnoses are extensive.

“Normal” has different meanings. In the context of physical or laboratory measurements, “normal” may mean “average,” “disease-free,” or “within a given statistical range.” However, it is important to know the characteristics of the population yielding “normal” values before deciding whether these values provide an appropriate reference range with which to compare an individual test result. Many laboratories now print reference ranges on their reports and highlight test values that fall outside these values as “abnormal.” When the test subject is a pregnant woman, a fetus, or a newborn, and the reference population is composed predominantly of middle-aged men, then comparisons are patently inappropriate. It is important to understand how the physiologic changes of pregnancy affect the results of various tests and measurements before deciding whether an out-of-range result is actually abnormal.

Drug use during pregnancy and lactation remain underdeveloped areas of clinical pharmacology and drug research. Pregnancy risk factors together with an increased incidence of chronic diseases and a rise in the average maternal age predict medication use will continue to rise during gestation. Common exposure categories include over-the-counter (OTC) medication, psychiatric agents, gastrointestinal medications, herbals, vitamins, antibiotics, and topical products. Only a few medications have been tested specifically for safety and efficacy during human gestation. Profound physiologic changes occur during both normal and pathologic pregnancy that may dramatically alter drug clearance, efficacy, and safety. Under such circumstances, the danger of a drug to mothers, their fetuses, and nursing infants cannot be determined with any confidence until it has been widely used. It is important that women with medical disorders such as diabetes, hypertension, epilepsy, and inflammatory bowel disease continue necessary therapy while pregnant. Unfortunately, many physicians stop or delay medically important agents precisely because of the lack of information.

Each pregnancy is a unique, physiologically normal episode in a woman’s life. However, preexisting disease or unexpected illness of the mother and/or the fetus may complicate the pregnancy.

Rhesus alloimmunization has become a rare clinical entity, at least in industrialized nations. It is more than 80 years since neonatal hydrops, anemia, and jaundice were first recognized as a single disease characterized by perinatal hepatosplenomegaly, extramedullary hematopoiesis, and nucleated red blood cells (RBCs) on the peripheral smear. What followed is a fetal success story. Levine and coworkers identified a decade later that the rhesus (Rh) antibodies on the RBCs of affected but not unaffected neonates were the cause of the anemia. The basic “story” was 60% completed 7 years later when Chown proved that transplacental fetal-to-maternal hemorrhage was a cause of maternal isoimmunization. In 1961, hemolytic anemia became the first treatable fetal disease after Liley characterized its natural history and then successfully transfused affected fetuses intraperitoneally with adult RBCs. Freda and colleagues completed the basic story when they demonstrated in 1964 that passive immunization of Rh-negative individuals with Rh-positive antibodies prior to purposeful exposure to Rh-positive RBCs prevented immunization.

Modern antenatal care aims to optimize both maternal and fetal outcomes. The various methods of prenatal fetal surveillance are directed towards early detection and, sometimes, prevention of chronic fetal hypoxia. The fetal response to acute or chronic hypoxia varies and is modified by the preceding fetal condition. Prenatal fetal surveillance tools are useful in pregnancies that are at high risk of developing chronic fetal hypoxia, but less so for acute events (e.g., placental abruption). There is evidence that fetal surveillance in unselected low-risk population is not cost-effective and leads to unnecessary interventions. Therefore routine prenatal fetal surveillance techniques or tests are not universally adopted in this group.

Intra-amniotic infection/inflammation (IAI) is a frequent and important cause of spontaneous preterm labor and delivery. Indeed, it is the only pathologic process for which both a causal link with spontaneous preterm birth has been established and a molecular pathophysiology defined. Fetal infection/inflammation has been implicated in the genesis of fetal and neonatal injury leading to cerebral palsy (CP) and chronic lung disease. Pathologic intra-amniotic inflammation can occur in the absence of detectable microorganisms, upon analysis by cultivation and/or molecular microbiologic techniques. This condition is known as sterile intra-amniotic inflammation and has been observed in patients with preterm labor and intact membranes, preterm prelabor rupture of the membranes (PPROM), and a short cervix. A mild sterile inflammatory process also participates in spontaneous labor at term, but this is considered to be an example of physiologic inflammation similar to that implicated in other important events in reproductive physiology, such as ovulation and implantation.

Complications arise more frequently during the first trimester than at any other stage of pregnancy. Most present with bleeding, pain, or both. Vaginal bleeding occurs in about 20% of clinically diagnosed pregnancies. It causes considerable anxiety for the woman and her partner. In the vast majority of cases, no intervention alters the outcome. The main aim of clinical management is a prompt and accurate diagnosis, with reassurance if the pregnancy is appropriately developed and viable, or appropriate intervention if not. This chapter focuses on the principles of diagnosis and management and three principal diagnoses: miscarriage, ectopic pregnancy, and gestational trophoblastic disease. The other differential diagnoses are shown in Table 5.1.

Imagine asking yourself the question, “How would I describe a typical pregnant woman who uses drugs?” You might reply that she comes from a different social class, cannot think beyond the pregnancy, uses jargon, and doesn’t listen or care about the welfare of the child. However, my experience when asking drug-using women what they thought about the typical obstetrician is that they say the doctor was from a different social class, could not think beyond the pregnancy, used jargon, and didn’t listen or care about the welfare of the child.

Postpartum hemorrhage (PPH) is the leading direct cause of maternal death in both industrialized and nonindustrialized nations, second only to preexisting conditions and indirect causes of maternal death.