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Pregnancy, Lactation, and Contraception: Assessment and Associated Dental Management Guidelines

PREGNANCY, LACTATION, AND CONTRACEPTION

Many providers in the past were hesitant about providing care during pregnancy out of fear for the safety of the fetus and the mother and uncertainty of the safety of local anesthetics, analgesics, and antibiotics. We now know that pregnancy does not contraindicate dentistry and dentistry can occur throughout pregnancy, give or take a few weeks. Dentistry is safe for the mother and safe for the fetus. Maintaining optimal oral health helps control oral disease, and this in turn reduces the transmission of pathogens from mother to child. Preventative services should be given during early pregnancy, and the provider must treat acute infections immediately.

A knowledgeable provider is a more confident provider. The goal of this section is to provide you with the knowledge of the current concepts associated with pregnancy, lactation, and contraception so you can proceed with confidence in the dental setting.

Pregnancy Overview

In order to know how and when to proceed with dentistry one needs to understand the symptoms, signs, and tests associated with pregnancy. The practitioner should be aware of the medications that can and cannot be used during pregnancy, as well as facts regarding radiation exposure during pregnancy.

Pregnancy and Trimesters

The 40 weeks of pregnancy are divided into three trimesters: The first trimester spans from 1–14 weeks, the second trimester spans from 14–28 weeks, and the third trimester spans from 28–40 weeks.

Some facts to remember: Development of organ systems occurs during the first trimester, and many organ systems are laid down by about eight weeks. By the third trimester, the placenta and the fetus together weigh about 13lb, on average. Therefore, in the supine position, this mass can potentially exert pressure on the thin walled inferior vena cava (IVC), causing it to collapse, or the gravid uterus can actually obstruct the IVC, leading to supine hypotension. The aorta is not affected, as it is a thick-walled blood vessel. Supine hypotension can be avoided by giving the patient a left lateral semi-sitting position in the chair to begin with, so the gravid uterus no longer presses on the IVC.

Assessment during the initial dental visit: During the pregnant patient’s first dental visit, determine the stage of her pregnancy. Determine if she is experiencing any pregnancy-associated symptoms that need to be accommodated. Assess if she is presenting with acute dental problems or if the patient is in for routine dental care. All emergency and routine care can continue during pregnancy. You must make provisions for and confirm her comfort in the dental chair throughout the duration of the dental appointment.

Pregnancy-Associated Symptoms and Signs

The early symptoms and signs of pregnancy are described in the following sections.

Amenorrhea

Conception occurs 14 days after the first day of the previous menstrual cycle. A patient having regular menstrual periods will know when her cycle is delayed and if she is pregnant. It is always important to ask your patient if she could be pregnant and when was the last menstrual period (LMP).

Nausea and Vomiting

“Morning sickness” can occur at any time of the day; it does not have to be in the morning only! It lasts for a few days or weeks and it is best not to schedule dentistry during this period of discomfort.

Urinary Frequency

Urinary frequency exists throughout pregnancy and the patient may need to excuse herself during dental treatment.

Fatigue

The patient more commonly complains of fatigue in the first and third trimester. It is better to schedule shorter appointments to prevent further exhaustion.

Pregnancy Tests

Tests confirming pregnancy are:

PREGNANCY-ASSOCIATED CHANGES

Pregnancy-associated changes experienced by the mother are generalized and knowing what areas are affected will help you better manage your patient. There are dietary, cardiovascular, gastrointestinal, and oral-cavity related changes.

Dietary Changes

The daily caloric, protein, and folic acid requirements increase, and lack of folic acid can lead to spina bifida in the fetus. The patient gains about 25–35 lb throughout the pregnancy.

Cardiovascular Changes

Several cardiovascular changes occur as the pregnancy advances.

Pulse

The pulse rate increases by 10–15 beats/min during pregnancy. Having knowledge of the baseline pulse rate prior to pregnancy always helps to calculate the actual change in pulse rate for the patient.

It is always advisable to decrease the amount of epinephrine in the local anesthetic, or to avoid epinephrine in a patient visibly affected with tachycardia.

Cardiac Output

The cardiac output increases by 40% in the first trimester. There is increased stroke volume from increased plasma volume. This is associated with increased vascularity in all areas of the body, including the gum tissue.

Cardiac output changes cause blood pressure changes in the mother. It is always important to monitor the blood pressure throughout the pregnancy. A diagnosis of hypertension is made when the current BP shows changes compared with the pre-pregnancy BP or the BP prior to 20 weeks of pregnancy.

An increase in the systolic BP by 30 mmHg and/or the diastolic BP by 15 mmHg indicates hypertension. Any BP reading >140/90 mmHg, if previous readings are unknown, also indicates hypertension.

It is important to remember that the blood pressure usually decreases in the second trimester because of vasodilatation. You need to stop all planned/routine dental treatment and refer the patient to the obstetrician immediately if the second trimester BP shows no change, or if there is an increase when compared to the first trimester BP readings. The obstetrician needs to evaluate and treat this patient for any pregnancy-associated hypertension before you can continue with dentistry.

Supine Hypotension

Supine hypotension as previously discussed usually occurs in the third trimester due to compression of the inferior vena cava by the gravid uterus. Supine hypotension must be prevented in the dental chair because it can cause the patient to pass out. When the patient passes out, the uterine blood flow gets affected and this causes the baby’s heart rate to decrease.

The best preventive treatment for supine hypotension is to turn the patient, preferably to the left side, to displace the uterus away from the inferior vena cava. The patient can also be placed in a sitting position with the knees flexed.

Supine hypotension presentation and management: During supine hypotension, the patient feels faint and the vision goes gray, plus the patient experiences dizziness. The blood pressure drops because of decreased venous return and decreased blood flow to the uterus. Also, with the supine position and consequent compression of IVC, there is lack of venous return from the lower extremities, which results in decreased cardiac output, adding to the hypotension due to the supine position.

Treatment of supine hypotention consists of sitting the patient up, or you can fully recline the chair and roll the patient toward her left side (this is the all-important left lateral position) to push the weight of the gravid uterus off to the left and away from the IVC.

Gastrointestinal Changes

The gums can become hyperemic and bleed during pregnancy. It is advisable to stress good, daily oral hygiene and schedule hygiene appointments at shorter intervals. The gastric emptying is delayed and this accounts for the increased risk of aspiration. This increased risk of aspiration is especially of concern during general anesthesia, so spinal or epidural anesthesias are preferred. This also avoids any threat of sedating the baby. General anesthesia is best avoided in the dental setting.

Oral Cavity Changes

Pregnancy-related oral cavity changes seen are pregnancy gingivitis, pregnancy tumor, and periodontal disease. Periodontal disease affects about 15% of individuals in the childbearing age and up to 40% of pregnant women. There is a disproportionate burden among low-income women, and advanced age, smoking, and diabetes increase the risk for periodontal disease. Dental carious lesions may become exacerbated during pregnancy, but the incidence of caries is not increased by pregnancy.

Pregnancy Gingivitis

Pregnancy gingivitis is relatively common and occurs in 50–70% of patients. There is an increased incidence of inflammation, erythema, edema, and hypertrophy of the gums with pregnancy gingivitis.

Pregnancy-associated hormonal changes cause increased growth of gum capillaries resulting in hypertrophy of the gums. The shift in hormonal changes also causes a shift in the bacterial flora and increased bacterial growth at the gum-line. The gums swell, bleed easily, and become sensitive.

The process begins around the second month of pregnancy and peaks in the middle of the third trimester. However, pregnancy gingivitis usually disappears postpartum. The dentist may need to implement scaling and root planing to correct or improve the gingivitis and prevent plaque growth.

Pregnancy gingivitis was thought to cause premature birth and low birth weight. The hypothesis was that bacteria from the pregnancy gingivitis–associated plaque entered the bloodstream and stimulated the patient’s immune system to produce prostaglandins. Prostaglandins in turn were thought to trigger uterine contraction leading to early labor, premature birth, and a smaller-sized baby. All these theoretical concerns that gram-negative bacteria associated with periodontitis increase the risk through bacteremia, causing an increase of preterm delivery and low birth weight, have now been put to rest. The study by Novak et al. (2008) examined periodontal treatment starting before 21 weeks pregnancy, and this study showed that even though periodontal care significantly reduced levels of bacteria associated with periodontitis, these periodontitis-associated bacteria were not associated with preterm birth. Thus, meticulous oral hygiene should continue in the pregnant patient, but periodontal care has no effect on birth weight or premature birth.

Pregnancy Tumor

The pregnancy tumor or “pyogenic granuloma” is a pedunculated outgrowth from the palatal surface of the gingiva and is usually found between the teeth or is associated with areas of local trauma or irritation. The tumor is usually anterior and maxillary in location. It is an inflammatory immune system response to an irritant, and in this case plaque acts as an irritant. Pregnancy tumors occur in about 10% of all pregnancies, but they disappear after birth. Pregnancy tumors can also be found on the face, hands, or arms.

The pregnancy tumor is painless and appears as a soft, gray tissue mass with a red border. Surgical excision after birth is the treatment of choice, but it can recur.

TERATOGENIC DRUGS AND FDA DRUG CATEGORIES

Teratogenic Drugs Facts

Teratogens are drugs or factors that can cause permanent alteration in the formation, functioning, or anchoring of the fetus. Organogenesis occurs during weeks 3–10, and structural malformations or morphological abnormalities due to teratogens can occur during these weeks. The CNS, limbs, heart, palate, and teeth are formed during this time. The brain and heart are vulnerable organs, and outcomes of insult include functional defects and morphological abnormalities. It is best to avoid dental drugs and routine dentistry during these weeks. The baby is completely formed at 35 weeks, and prior to this point the fetus is vulnerable to changes caused by adverse teratogenic drugs or factors.

Some of the Category B opioid pain medications that are safe during pregnancy become Category C/D toward the time of delivery and should not be used closer to term. These specific drugs are discussed in further detail in this chapter.

To have a better understanding of what medications should be used and what should be avoided in the pregnant patient, one has to have a good understanding of the FDA drug categories and specific drug facts. Drugs that are Category A or B are safe drugs to use during pregnancy.

FDA Drug Categories

The following are FDA drug categories:

DRUGS CONTRAINDICATED DURING PREGNANCY

Drugs Absolutely Contraindicated During Pregnancy

• Accutane: Accutane is associated with severe congenital abnormalities.
• Amiodarone: Amiodarone is an anti-arrhythmia drug.
• Angiotensin-converting enzyme (ACE) inhibitors.
• Ciprofloxacin (Cipro): Cipro affects fetal kidneys and it should be completely avoided during pregnancy.
• Live attenuated vaccines: Includes varicella and MMR.
• Methotrexate: Methotrexate is associated with a high rate of miscarriage.
• Oral hypoglycemic drugs: These drugs can cause hypoglycemia in the fetus.
• Prostaglandins: These drugs promote miscarriage.
• Radioactive iodine: Radiation exposure occurs.
• Sumatriptan succinate (Imitrex): An anti-migraine drug, vasoconstrictor in action, that can cause growth restriction.
• Tetracyclines: These affect teeth and bone growth.
• Warfarin (Coumadin): Heparin is used instead, if blood thinning is required.

RADIATION AND PREGNANCY

The following are important facts to know about radiation:

• No single diagnostic x-ray procedure results in radiation exposure to a degree that would threaten the well-being of the developing pre-embryo, embryo, or fetus. Radiation exposure <5 RADS is considered safe. Risk of anomalies, growth restriction, or abortions is not increased with exposure >5 RADS. Even multiple x-ray exposures seldom result in this level.
• During routine maternal dental x-rays, the fetal exposure is <0.01 RADS and <.004 RADS for a skull film. This is because exposure to mother and fetus are not the same. Additionally, shielding is used and that minimizes exposure.
• Daily background radiation is 0.0004 RADS. Moderate amount of radiation exposure is not harmful in pregnancy. It is important to inform and educate your patient in order to minimize anxiety.
• Chest x-ray exposure radiation dose is 0.008 RADS.

Fetal Risks with Improper Radiation Exposure

The following are fetal risks with radiation exposure:

GENERAL ANESTHESIA AND PREGNANCY

General anesthetic can affect the fetus if it crosses through the placental circulation. General anesthesia should not be given near the time of delivery because it will impair the infant’s breathing. General anesthesia will also prolong the gastrointestinal transition time in the mother and thus increase the risk of aspiration.

Chronic N2O exposure can be hazardous. This is more relevant to women working in your office rather than the pregnant patient. Women chronically exposed to N2O have an increased rate of spontaneous abortions or give birth to infants with congenital abnormalities. Chronic N2O exposure also accounts for the reduced rate of fertility among such women.

SUGGESTED GENERAL PRINCIPLES OF PREGNANT PATIENT CARE

Follow these guidelines: