© 2017, GENASSIST, Inc.    

By Keith S. Wexler, MBA, Maternal Fetal Medicine, Prenatal Diagnosis and Biotech/Life Sciences Consultant, GENASSIST, Inc.

Paul Wexler, M.D., F.A.C.O.G., Medical Director, GENASSIST, Inc.

Clinical Professor, Department of OB/GYN, University of Colorado Health Sciences Center

Clinical Professor, Division of Genetics/Dept. of Pediatrics, Univ. of Colorado/The Children’s Hospital

PATERNAL AGE:

If Paternal Age is Greater than 40 years: Several studies in the 1980’s and the early 1990’s suggested a slight increased risk for children with a new disease for the family due to a change in a gene inherited from an older father.

Also, the possibility of a slightly higher incidence of Down syndrome was raised. When the age of the mother is taken into account, there appears to be little, if any, increased risk (less than 1%) for Down syndrome due to paternal age.

It is not possible to test for all conditions due to a mutation in a gene due to advanced paternal age. Couples who are concerned are encouraged to have a Level II ultrasound between 15 and 22 weeks gestation.

Amniocentesis for advanced paternal age is not medically recommended but may be justifiable in some families.

*A recent study, that is ongoing, has suggested a possible relationship between increasing maternal age and/or paternal age (greater than 40 years) and autism in a child. Reference: Israel & Mt. Sinai, NY. *Some recent studies have suggested risk may be as high as 1:50 to 1:80.

MATERNAL AGE:

Since approximately 1972 when amniocentesis first became available for prenatal diagnosis for genetic testing, the basis for recommending the procedure was based upon the theory that since a woman is born with all the eggs she will have in her lifetime she will have a greater chance of having a child with a chromosome abnormality as she ages.

(Table 1) illustrates the percentage of babies born with a chromosome abnormality for every 100 pregnancies in that group.

The 35 year old has an asterisk (*) because this was selected by the American College of OB/GYN as the age at which patients need to be offered prenatal diagnosis by Chorionic Villus Sampling (CVS) or amniocentesis because the patient has a greater risk of having an abnormality than miscarrying from the procedure (1 in 270 procedures).

In 2007, the American College of OB/GYN allowed all women of all ages to have the option of amniocentesis regardless of age since the miscarriage risk in four published studies was found to be as low as 6 per 10,000 procedures (0.06%) which is less than a maternal age related risk alone.

*In the article “Procedure-related risk of miscarriage following amniocentesis and chorionic villus sampling: a systematic review and meta-analysis” in Ultrasound Obstet Gynecol. 2015 Jan;45(1):16-26 by Akolekar R et al, the procedure related risk following amniocentesis was 0.04% to 0.26% and following CVS was 0.22%.

(TABLE 1)

Maternal Age Less Than 20 Years Old                                      0.05% to 0.08% risk

Maternal Age 20 to 24 Years Old                                                0.08% to 0.10% risk

Maternal Age 25 to 29 Years Old                                                0.08% to 0.15% risk

Maternal Age 30 to 34 Years Old                                                0.12% to 0.20% risk

*Maternal Age 35 to 39 Years Old                                              0.30% to 0.80% risk

Maternal Age 40 to 42 Years Old                                                0.90% to 1.50% risk

Maternal Age 43 to 45 Years Old                                                1.50% to 3.00% risk

Maternal Age 46 to 49 Years Old                                                2.00% to 10.00% risk

Maternal Age Greater Than 50 Years Old                                 Greater than 10.00% risk