Prior to conception, any patient desiring fertility has an opportunity to
insure her health is optimal for a pregnancy. Her health care provider is in
a unique position to offer counseling on medical care and behavior modification,
if applicable. This article will address appropriate preconception screening.
Medical/ Surgical History
When medical conditions are present, often more control is required to reduce
pregnancy complications. This is most evident in hypertension and diabetes where
medications are limited due to teratogenicity concerns and target goals are stricter.
Regarding thyroid disease, disorders involving antibodies (antimicrosomal) have
been associated with a higher risk of miscarriage and preterm delivery. Low dose
thyroid replacement in euthyroid patients with antimicrosomal antibodies may
reduce these complications as suggested in a Journal of Clinical Endocrinology & Metabolism
article. Additionally, thyroid replacement is recommended in subclinical hypothyroid
pregnant patients to reduce cognitive developmental problems in the fetus. This
is due to the fetus being dependent on adequate maternal thyroid levels during
the first trimester until independent thyroid function begins.
While extremes of body weight have been known to influence and even cease
ovulation function, elevations of body mass index have now been shown to reduce
pregnancy rates particularly with In-vitro Fertilization. As a result, ideal
body weight before pregnancy will improve pregnancy rates and reduce gestational
hypertension and diabetes, still birth and Cesarean section.
Physical examination may suggest indolent disease such as insulin resistance
(acanthosis nigricans) often found in Polycystic Ovarian Syndrome patients. A
CBC should also be included in any women contemplating pregnancy to screen for
anemia.
Genetic History
Certain populations are more susceptibility to particular hereditary genetic
diseases. The following screens are recommended to avoid affected offspring (see
Table). Both parents require testing when one is a carrier and are then referred
to a genetic counselor to discuss transmission risk. In-vitro Fertilization with
Preimplantation Genetic Diagnosis is an exciting technology now available at
our center and a select others to screen embryos for the known genetic disease
to avoid inheritance and virtually eliminate the disease from the family gene
pool.
| Disease |
Population at risk |
| Cystic fibrosis |
Caucasian of European and Ashkenazi Jewish Descent |
Sickle cell
|
African American |
| Tay-Sachs |
Ashkenazi Jews, French Canadians, Cajuns |
| Beta-thalassemia |
Mediterranean, Southeast Asian, African American |
| Alpha-thalassemia |
African American and Asian, especially from Thailand |
| Gaucher’s, Canavan, and Niemann-Pick |
Ashkenazi Jew |
Medications
The PDR is a valuable tool to determine the pregnancy category of any medication.
As the category rating increases from A, B, C, and D, the medication is carefully
prescribe to weigh the risk vs. the benefit. Category X medications are absolutely
contraindicated in pregnancy. All physicians should consult the pregnancy category
of a drug when prescribing for women of reproductive years that are not using
reliable contraception to avoid the risk of teratogenicity.
Fortunately, there is enough evidence that folic acid can greatly reduce the
risk of neural tube defect so it is imperative to place all pregnant women (preferably
three months before conception) on adequate folic acid at least 0.4mg per day.
Most prenatal vitamins contain 1mg of folic acid.
Immunizations
Three viruses that can cause significant pregnancy complications are rubella,
varicella, and hepatitis B. Since all of these now have effective vaccines, they
should be screened in women desiring conception. Rubella can be administered
as part of the MMR and, along with the varicella vaccine, now only requires a
one month delay in conception as recommended by the CDC. Whereas rubella is a
single dose vaccine, varicella and hepatitis B require two and three vaccinations,
respectively. HIV screening is strongly recommended by the American College of
Obstetricians and Gynecologists. Other STDs and tuberculosis can be screened
as clinical suspicion dictates.
Miscellaneous
Substance abuse counseling should include cigarette smoking cessation since
risk with pregnancy includes low birth weight, placental abruption, preterm rupture
of membranes, avoiding excessive alcohol, or recreational drug use. Domestic
abuse and violence should be asked of all women, particularly preconception since
pregnancy may increase the susceptibility of women. Nutrition/Environmental concerns
include maintenance of a proper diet and avoidance of inadvertent X-ray exposure.
To quote an old axiom, “An ounce of prevention will always been
better than a pound of cure.”
Mark P. Trolice, M.D., FACOG, FACS is Director of Fertility C.A.R.E. (Center of Assisted Reproduction & Endocrinology in the Orlando, Florida area and Director of Reproductive Endocrinology & Infertility at Arnold Palmer Hospital for Children & Women.
© Mark P. Trolice Copyright 2010
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