Adaptations to Pregnancy and Related Nursing Care

Adaptations to pregnancy include physiologic and psychosocial changes that occur in a pregnant patient in response to a developing fetus.

Physiologic changes during pregnancy affect the body from head-to-toe, including the cardiovascular, respiratory, and reproductive systems.

Starting with the cardiovascular system, pregnancy is considered a high-volume state, meaning that blood volume gradually increases during the pregnancy to provide circulation to expanding maternal tissues; exchange nutrients, oxygen, and waste in the placenta; and create a reserve for blood loss during delivery.

The composition of blood changes too. Both plasma and red blood cells increase; although there’s a larger increase in plasma, which leads to dilutional anemia, sometimes referred to as a physiologic anemia of pregnancy, where hemoglobin and hematocrit levels are decreased.

White blood cells, primarily neutrophils, increase along with clotting factors, like VII, VIII, X, and fibrinogen. Increased clotting factors minimize bleeding after delivery but also increase the risk of venous thromboembolism.

Now, in order to pump the extra blood and increase cardiac output, the heart rate increases by 10 to 15 beats per minute; the stroke volume, or the amount of blood pumped with each heartbeat, increases as well; and the heart enlarges from this extra workload.

In fact, the uterus also enlarges and pushes on the diaphragm, causing the heart to be slightly displaced up and to the left.

Blood pressure decreases despite increased blood volume, due to elevated progesterone and estrogen, which cause vasodilation and decreased vascular resistance, increasing the risk of orthostatic hypotension.

Moreover, when lying flat, the weight of the uterus can compress the inferior vena cava, reducing blood return to the heart.

As a result, cardiac output decreases and supine hypotension occurs, causing dizziness and lightheadedness. Also, as less blood circulates to the placenta, fetal hypoxia can occur.

This can be avoided if patients turn to their side or place a pillow under their lower back when lying down, to relieve pressure from the inferior vena cava and restore venous return to the heart.

Next, there are changes in the respiratory system to accommodate an increase in oxygen consumption. Tidal volume, or the amount of air inhaled and exhaled with each breath, rises along with respiratory minute volume, or the amount of air breathed every minute, increasing the amount of oxygen and carbon dioxide exchange.

As the expanding uterus places pressure on the diaphragm, the lungs have less room to expand, which can cause shortness of breath until the fetus descends into the pelvis later in the third trimester.

Additionally, elevated progesterone levels increase the sensitivity of the respiratory center in the medulla oblongata and decrease airway resistance.

Now in the reproductive system, increased progesterone and estrogen promote breast development and preparation for lactation.

Blood flow also increases to support the growth of breast tissue. Together, these changes can cause symptoms like tingling, fullness, and tenderness of the breasts.

Other important changes include leakage of colostrum, or a thin, yellow fluid that signals the beginning of breast milk; and hypertrophy of Montgomery tubercles which are sebaceous glands that lubricate the nipples.

The uterus expands from the pelvis to the abdomen and reaches the xiphoid process by 36 weeks of gestation, and its smooth muscle cells increase in size and number.

At the same time, the number and size of blood vessels increase to provide nutritional support to the enlarging uterus. Patients may feel irregular, brief uterine contractions, called Braxton-Hicks contractions, which typically increase in strength and frequency as the pregnancy progresses.

Also, cervical glands increase in number and activity, secreting thick mucus that forms a plug to block the cervical canal and prevent harmful organisms from entering the uterus.

Likewise, the vagina becomes more acidic to protect the fetus from harmful organisms. On the other hand, vaginal secretions increase, which contain high levels of glycogen, which promotes the growth of Candida albicans, making yeast infections more likely.

Other vaginal changes include increased blood flow, thickened vaginal mucosa, more prominent rugae or internal ridges, and softening of connective tissues to prepare for delivery.

Along with physiologic changes, pregnant patients experience psychosocial changes. In the first trimester, they may feel uncertain until pregnancy is confirmed; and they may experience ambivalence, or internal conflict, or as they consider the life changes and responsibilities that come with parenthood.

During this time, patients often focus on themselves, and how pregnancy symptoms like nausea and fatigue affect them, and they may experience changes in mood or sexual desire from hormone fluctuations which can continue throughout pregnancy.

In the second trimester, body changes, such as weight gain, breast enlargement, and bulging of the abdomen, cause the reality of pregnancy to set in.

As patients hear fetal heart tones, see the fetus during ultrasounds, and feel fetal movement, they become more focused on their developing infant.

Throughout the third trimester, patients may experience increased vulnerability, dependence on others, and desire for reassurance and attention.

To prepare for the infant’s arrival, patients typically purchase infant supplies and take childbirth classes, and as their due date approaches, they may grow more anxious about their impending labor and delivery.

Alright, as a quick recap…Adaptations during pregnancy include physiologic and psychosocial changes that occur in response to a developing fetus.

Physiologic changes include cardiovascular, respiratory, and reproductive changes, whereas psychosocial changes affect patients throughout each trimester as they prepare for their infant’s arrival.