Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Clinical Applications of Three-Dimensional Sonography in Obstetrics

Three-dimensional (3D) and four-dimensional (4D) ultrasonography (US), also referred to as volume sonography, have developed significantly in recent years. Two-dimensional (2D) US remains the backbone of sonographic imaging, to which 3D and 4D US have contributed an additional layer of problem-solving tools. This chapter addresses the obstetric applications of 3D US. Basics of Volume Sonography Volume data sets are typically obtained with a 3D mechanical probe…

Doppler Ultrasound: Select Fetal and Maternal Applications

Though gray-scale ultrasound is ubiquitous in contemporary obstetric practice, it is limited in its ability to assess fetal hemodynamic status. Adding color, power, and pulsed Doppler ultrasound functions greatly improves understanding of fetal circulation and hemodynamic status. Doppler ultrasound detects frequency shifts caused by relative motion of a target compared to the transducer. Each vessel has a unique blood flow velocity waveform (FVW), which can be…

Performing and Documenting the Fetal Anatomy Ultrasound Examination

The midtrimester fetal ultrasound examination (“anatomy scan”) serves as an important checkpoint for evaluation of the pregnancy and its potential risks. It affords an opportunity to compare obstetric dating with fetal biometric measures, and it permits, prior to fetal viability, identification of important structural abnormalities that may significantly alter neonatal prognosis and management. Finally, it allows identification of maternal uterine findings such as uterine fibroids and…

Evidence-Based Practice in Perinatal Medicine

All those who drink of this remedy recover in a short time, except those whom it does not help, who die. Therefore, it is obvious that it fails only in incurable cases. Galen (circa AD 100) Evidence-Based Medicine in Perspective Many of the improvements in medical care for women in the past 30 years and tools to tackle emerging challenges have resulted from carefully designed studies…

Placental Respiratory Gas Exchange and Fetal Oxygenation

Knowledge of respiratory gas exchange across the human placenta depends on integrating observations in pregnant patients with experimental findings in laboratory animals. The evidence in laboratory animals consists of a fairly comprehensive set of data in sheep, with chronically implanted vascular catheters in the maternal and fetal circulations, and a more limited but important set of data in other mammals. Transport of Atmospheric Oxygen to Fetal…

Fetal Cardiovascular Physiology

Blood Flow Patterns and Oxygen Delivery In the mammalian adult, oxygenation occurs in the lungs, and oxygenated blood returns via the pulmonary veins to the left side of the heart to be ejected by the left ventricle into the systemic circulation. In the fetus, gas exchange occurs in the placenta, and the fetal lungs are nonfunctional as far as the transfer of oxygen and carbon dioxide…

Maternal Nutrition

Sufficient intake of nutrients during pregnancy is essential to meet the demands of fetal growth and development as well as maternal physiologic adaptations to pregnancy. The nutritional status of pregnant women in the United States is suboptimal , owing to many factors, including access to and price of healthy foods, knowledge of a healthful diet, and pressing needs that may take priority over a healthful diet.…

The Breast and the Physiology of Lactation

Universal breastfeeding is recommended by the American College of Obstetricians and Gynecologists (ACOG), the World Health Organization (WHO), the United Nations Children’s Fund (UNICEF), the American Academy of Pediatrics (AAP), and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), but recommendations alone are not sufficient to promote breastfeeding. It is the responsibility of every physician to recommend and promote breastfeeding enthusiastically and support…

Endocrinology of Pregnancy

The concept of the fetus, the placenta, and the mother as a functional unit originated in the 1950s. More recent is the recognition that the placenta itself is an endocrine organ capable of synthesizing virtually every hormone, growth factor, and cytokine thus far identified. The premise that the placenta, composed chiefly of two cell types—syncytiotrophoblast and cytotrophoblast—can synthesize and secrete a vast array of active substances…

Maternal Cardiovascular, Respiratory, and Renal Adaptation to Pregnancy

Profound physiologic changes occur in the cardiovascular, respiratory, and renal systems during pregnancy. These adaptations begin soon after conception and continue as gestation advances, yet most are almost completely reversed within weeks to months after delivery. These physiologic adaptations are usually well tolerated by the pregnant woman, but they must be understood so that normal changes can be distinguished from pathologic processes. Cardiovascular System Blood Volume…

Immunology of Pregnancy

Pregnancy as an Allograft Occurrences of recurrent abortion, preeclampsia, or hemolytic diseases of the newborn raise the rhetorical question, “Why did your mother reject you?” However, when considering the complexity of maternal-fetal immune interactions and the vast number of successful pregnancies, perhaps the more relevant question is “Why didn’t your mother reject you?” Over 50 years ago, the renowned transplant immunologist Sir Peter Medawar proposed a…

Pathogenesis of Spontaneous Preterm Birth

Preterm Birth Syndrome: Phenotypic Classification In humans, singleton pregnancies last on average 280 days (40 weeks) from the first day of the last menstrual period to the estimated date of delivery. Preterm birth (PTB) is defined as birth between 20 0/7 weeks’ gestation and 36 6/7 weeks’ gestation. Viability represents the potential of the fetus to survive outside the uterus after natural or induced birth. The…

Physiology of Parturition

Labor is the physiologic process by which the products of conception are passed from the uterus to the outside world, and it is common to all mammalian viviparous species. Considerable evidence suggests that the fetoplacental unit primarily controls the timing of physiologic labor in humans, although maternal factors are also involved. This chapter summarizes the current state of knowledge on the biologic mechanisms responsible for the…

Multiple Gestation: The Biology of Twinning

The incidence of multiple births has increased dramatically over the past 5 decades. In the United States, twin birth rates increased almost twofold between 1971 and 2014. This sharp increase in twin births has been linked to two related factors: older maternal age distribution and expanded use of fertility-enhancing therapies (assisted reproductive technologies [ART] and non-ART treatments such as ovulation stimulation). Improved reproductive technology has led…

Amniotic Fluid Dynamics

Amniotic fluid (AF) is necessary for normal human fetal growth and development. The fluid volume cushions the fetus, protecting it from mechanical trauma, and its bacteriostatic properties may help to maintain a sterile intrauterine environment. The space created by the AF allows fetal movement and aids in the normal development of both the lungs and the limbs. Finally, AF offers convenient access to fetal cells and…

Normal Early Development

Miscarriage, fetal growth restriction, and preeclampsia are pathologies generally arising from events that go awry in the early developmental period. Most fetal malformations arise in early embryogenesis. Thus to accurately diagnose and design effective treatments for these conditions, an understanding of early human development is essential. Normal early placental and embryonic development requires a complex sequence and array of signaling pathways, cell-cell communication, and decidua-embryo and…

Molecular Genetic Technology

Detecting the Genetic Basis of Disease Genetic Variation Each human being’s complete genetic sequence reveals a significant amount of genetic variation. The collection of single nucleotide variations and copy number variations within an individual forms a genetic backdrop that influences how a person looks, grows, and physiologically responds to stressors such as a disease or medication. Population sampling has demonstrated that, among healthy individuals, the genetic…

Human Genetics and Patterns of Inheritance

The Human Genome Project was completed on October 21, 2004, and provided the primary structure (nucleotide sequence) of all chromosomes. However, in the nearly 150 years preceding this breakthrough, there were major discoveries that were equally relevant. Gregor Mendel, known as the father of modern genetics, described the most basic modes of inheritance and provided an early understanding of human genetic variability. The double helix structure…

In vitro fertilization

Key points For in vitro fertilization (IVF) with and without intracytoplasmic sperm injection, the delivery rate per cycle in which ova are retrieved is as high as 50%, depending on the age of the woman. The rate of pregnancy after IVF is directly related to the number of embryos placed in the uterine cavity. Strict guidelines set forth by American Society for Reproductive Medicine (ASRM), which…

Infertility: Etiology, Diagnostic Evaluation, Management, Prognosis

Key points Infertility is considered to be a disease and affects approximately 7% of all U.S. couples of reproductive age—more than 7 million women in the United States. A systematic evaluation of factors involved in infertility should be carried out rapidly, along with markers of ovarian reserve (antral follicle count, antimüllerian hormone); this will help frame the discussion with couples as to how best to proceed…