Pinky Ronen, M.D.
Preconception evaluation and counseling provide an opportunity to inform women about fertility/pregnancy issues, identify some of the risks of pregnancy for the mother and fetus, educate them about these risks, and institute appropriate interventions, before conception. Preconception care is very important for prevention of congenital anomalies since many women initiate their prenatal care late during, or even after organogenesis ( the development of organs which is completed by 8-10 weeks for the most part).
The key task in identifying risks to the woman and her pregnancy is to obtain a thorough history. The following topics may pose risk to the pregnancy:
A complete medical history is useful for discussing how pregnancy can affect maternal medical conditions and the effect of a medical disorder on the fetus and pregnancy. Optimal management of maternal medical conditions, including changes in medications to incorporate medications known to be safer in pregnancy, is an important step. Some common or serious medical conditions that impact or are impacted by pregnancy are discussed briefly below, additional disorders are reviewed separately
Advanced maternal age is associated with increased pregnancy risks that include infertility, fetal aneuploidy, gestational diabetes, preeclampsia, and stillbirth. Women should be aware of these risks and the consequences of delaying conception until they are over 35 years of age.
The gynecologic and obstetric histories are important for identifying factors that may contribute to infertility or complications in a future pregnancy. Uterine anomalies, as an example, can be associated with recurrent pregnancy wastage or preterm birth. The recurrence risk of an adverse outcome (eg, miscarriage, preterm birth, intrauterine growth restriction, preeclampsia, congenital anomaly, perinatal death) should be discussed with women who have a history of pregnancy complications. In some cases, interventions to reduce or eliminate the risk of recurrence are available.
Evaluation of the patient's family history helps to identify genetic risks to the fetus and maternal medical risks that may not have been appreciated. As an example, a woman may not be aware that a family history of thromboembolic disease can put her at risk for thromboembolic and pregnancy complications.
Exposure to tobacco, alcohol, and illicit drugs can be harmful to both the mother and fetus. Thus, it is important to screen women for use of these substances.
Use of tobacco in pregnancy has been associated with several adverse outcomes, including miscarriage, prematurity, and low birth weight.
A spectrum of birth defects related to alcohol intake during pregnancy may occur, ranging from subtle growth retardation and neurobehavioral effects with moderate alcohol intake, to the fetal alcohol syndrome with heavy use. It has been estimated that more than half of women of childbearing age who do not use contraception (and thus are at risk of getting pregnant) consume alcohol, with approximately 2 percent engaging in binge or frequent alcohol use. It is therefore important to elicit any history of alcohol consumption when evaluating a woman of childbearing age.
Illicit drugs have variable effects on pregnancy outcome that may be related to social disturbances in the mother, in addition to effects of the drugs themselves.
Psychosocial stress, mental health, and financial issues should be identified and appropriate interventions taken with the help of a community resource specialist. It is particularly important to screen for the presence of domestic violence, lack of social support, and barriers to prenatal care.
Environmental exposures — Questions about the woman's work, hobbies, pets, and home environment can identify potentially toxic exposure. Examples of such hazards include organic solvents used in manufacturing processes, toxoplasmosis risk from changing cat litter boxes or eating under-cooked meat, mercury from fish consumption, and lead used in arts and crafts.
Weight — Maternal obesity has been linked to subfertility, having a child with a congenital anomaly, and several other pregnancy complications (gestational diabetes, preeclampsia, cesarean delivery, macrosomia, difficult delivery, and stillbirth/early neonatal death).
The physical examination in the preconception evaluation is the same as for the routine periodic health evaluation. Important aspects to highlight include examination of the thyroid gland, breasts, heart, skin, and a pelvic examination. The pelvic examination should include cervical cancer screening and, for patients in whom it is indicated, screening for gonorrhea and chlamydia (see below). Dental caries and other oral diseases (eg, periodontal disease) also are common and may be associated with pregnancy complications, such as preterm delivery; thus, referral to a dentist is appropriate.
Laboratory assessment/screening — The choice of laboratory tests depends upon the general guidelines recommended for all pregnant women and the individual's personal medical history. Routine laboratory examination includes:
In addition to these tests, further testing may be considered in those patients with specific clinical indications.
Exposure to ionizing radiation — In addition to the above, women who undergo periodic screening tests (eg, mammogram, dental films, chest radiographs) involving ionizing radiation should schedule these tests prior to attempts at conception.
Interventions — After the pregnancy risk assessment is performed, preconception interventions are directed at preparing and educating the patient. These may include preconception glycemic control in diabetics, folic acid supplementation, avoidance of teratogens, and following a low phenylalanine diet in women with phenylketonuria .
Heritable diseases — For those with a positive history for a heritable disease, referral to a specialist in genetic counseling is usually required to discuss carrier testing, the risk of genetic disease in the fetus, options regarding prenatal diagnosis and intervention, and the natural course of the disease
Cessation of substance use — Smoking cessation and reduction during pregnancy improves pregnancy outcome. Women who are smokers should be counseled on the benefits of smoking cessation and offered resources to help them quit smoking.
There are no data to establish a safe threshold for alcohol consumption during pregnancy, thus the safest course of action is to abstain. Patients who use illicit drugs should be strongly advised of the risks of this behavior and referred to cessation programs in their area
Depression and psychotropic drugs — Patients with active symptoms of depression should be treated, if necessary, with drug therapy.
Nutrition and supplements — A nutritionist may be consulted to evaluate restricted diets or to offer advice on eating a well-balanced, healthy diet. A systematic review concluded that provision of preconceptional nutritional counseling improved pregnancy.
All women planning pregnancy or capable of becoming pregnant should be counseled to take a daily multivitamin with folic acid (400 to 800 mcg) to reduce the risk of neural tube defects.
Women with phenylketonuria (PKU) and high blood phenylalanine levels are at risk for having a baby with intellectual disability and congenital heart disease. Health care providers should advise affected women of childbearing age to either stay on a PKU diet or plan their pregnancies to occur after they have reinstituted such a diet.
The quantity and type of fish consumed should also be regulated and certain types of fish should be avoided during pregnancy and the preconception period due to concerns about possible teratogenic effects from environmental toxins. Only cooked fish should be eaten
Exercise — Mild to moderate exercise is not harmful to the healthy pregnant woman or her fetus.
Immunization — Ideally, a woman should be immune to or immunized against infections that place her or her fetus at risk. These diseases vary by country and personal risk factors (eg, pneumococcal vaccine after splenectomy). Nonpregnant women of childbearing age who may become pregnant should receive all clinically indicated immunizations, preferably at least one month prior to conception. In the United States, this means immunity (as a result of immunization or disease) to measles, mumps, rubella, tetanus, diphtheria, poliomyelitis, and varicella. Immunization issues with respect to pregnancy are discussed in detail separately.
Pregnant women are at an increased risk of complications related to influenza infection. It is therefore recommended that women who become pregnant during the influenza season receive the influenza vaccine regardless of stage of pregnancy.
Vaccination should be offered to a woman with a negative rubella titer and she should be advised to wait one month before attempting conception since this is a live attenuated virus vaccine.
Varicella infection during pregnancy can be associated with significant maternal and fetal morbidity and mortality. Administration of anti-varicella zoster immunoglobulin to the non-immune woman exposed during pregnancy may not always be effective in preventing clinical disease, although it can attenuate the risk to the fetus.
Patients at risk for hepatitis B infection (eg, women with multiple sexual partners, household contacts of patients with hepatitis B, healthcare workers) should be offered hepatitis B vaccine.
Precautions against infection — Some infections are potentially harmful in pregnancy, particularly in the first trimester. Interventions exist to minimize the risk of these infections .