The definition of maternal age greater than 35 years has been clarified to include mothers reaching the age of 35 by the EDC as opposed to being 35 at the time of the 1st prenatal visit.

Risks to Mother

Mothers at or older than 35 years may be at increased risk for the following:

        dysfunctional labor(1)

        cesarean delivery (Section A5 Previous Deliveries, page 224.00)

        gestational diabetes (Section C3 Glucose Intolerance I: GDM, page 278.00)

        late pregnancy bleeding (Section 6C Placenta Previa, page 92.00, Section 6C Abruptio Placentae, page 90.00)

        preeclampsia and hypertension (Section 7B Hypertensive Disorders of Pregnancy, page 137.00)

Overall, there seems to be a several fold increase in maternal mortality.

Risks to Fetus

There appears to be an increased incidence of the following:

        babies < 2500 gm (see Section A1 Small for Gestational Age, page 208.00)

        babies > 4000 gm (see Section A1 Large for Gestational Age, page 210.00)

        spontaneous abortions (see Section A3 IABs / SABs, page 216.00)

        stillbirth rate (see Section A4 Perinatal Death, page 219.00)

        possible mild association with neonatal mortality (Section A4 Perinatal Death, page 219.00)

        cesarean delivery (Section A5 Previous Deliveries, page 224.00)

        chromosome abnormalities (Section C12 Birth Defects, page 354.00)

Chromosomal Problems

It is important for women to understand the limitations of amniocentesis/CVS analysis. Every couple in the general population has a 3-4% risk of having a child with a birth defect or mental retardation that will NOT be found prenatally. Amniocentesis and CVS cannot guarantee a normal or healthy baby.

The mother should be given the pink patient education sheet 12 Amniocentesis as early as possible so that she can have the amniocentesis done at the optimal time if she desires it. If amniocentesis is elected, program as discussed in Section 12 Amniocentesis, page 182.00, using line 12 of the Flow Sheet.

CVS is best performed between the 10th and 12th week of gestation. As with amniocentesis, give the pink patient education sheet 12A Chorionic Villus Sampling and if elected, preplan this on line 12 of the Flow Sheet as described in Section 12A Chorionic Villus Sampling, page 184.00 of the manual.

Even if the patient states that she is not interested in an abortion if she were carrying an affected child, referral for genetic counseling may be appropriate as some patients may change their minds. Additionally, in one study, over 43% of patients had other risk factors and concerns that needed to be addressed besides maternal age.(4)

Gestational Diabetes

To screen for this, see Section 10 Gestational Diabetes Screening, page 176.00.

Paternal Age

There does not appear to be any significant increase in the risk of birth defects or chromosome abnormality with increasing paternal age. However, there is an increased risk of gene mutations predisposing the fetus to autosomal dominant and X-linked disorders. The exact risk for any specific disorder is small. Currently, it is not possible to screen prenatally for all autosomal dominant and X-linked diseases. Genetic counseling on an individual basis is recommended for couples to address their specific concerns, if advancing paternal age is an issue.

Patient Education

Distribute the pink patient education sheet A0 Pregnancy in Women 35 Years or Older.

Risk Factor

Enter to area 31 of the Flow Sheet: age over 35.


1.       Cohen WR, Newman L, Friedman EA: Risk of Labor Abnormalities with Advancing Maternal Age. Obstet Gynecol 55:414-416, 1980.

2.       Rubin SP, et al: Genetic Counselling Before Prenatal Diagnosis for Advanced Maternal Age: An Important Medical Safeguard. Obstet Gynecol 62:155, 1983.

3.       Buehler JW, Kaunitz AM, et al: Maternal Mortality in Women Aged 35 Years or Older: United States. JAMA 255:53, 1986.

4.       Martin RH, et al: The Effect of Age on the Frequency of Sperm Chromosomal Abnormalities in Normal Men. Am J Hum Genet 41:484, 1987.

5.       Salihu HM, et al: Pregnancy After Age 50 Poses Significant Risks to the Fetus. Obstet Gynecol 102:1006-1014, 2003.

Special Instructions

Upd IV,6,04