There are few data about the likelihood of women with OI developing complications during pregnancy. The wide variation in OI symptoms, coupled with the wide variation in pregnancy complications in all women, make it difficult to predict how pregnancy will affect a woman with OI.
Given that OI is a rare disorder, it may be difficult to find a doctor with experience treating women with OI, or managing pregnancies in which the fetus has OI. In general, it is recommended that women with OI who are pregnant or considering becoming pregnant consult a competent obstetrician/gynecologist. A specialist in high-risk pregnancies may be helpful for women who anticipate pregnancy complications, either due to severe OI-related problems, or other problems, such as a history of preterm labor, multiple miscarriages, or other significant health concerns. Planning to deliver at a hospital with special services for high-risk mothers and babies is another consideration.
Gynecologic Concerns of Women with OI
Obstetric Concerns of Women with OI
Talking with your doctor
A woman with OI should also talk to her physician about appropriate diet and exercise before, during and after pregnancy to ensure optimum health for both herself and her baby. A baby’s need for calcium during pregnancy and breastfeeding may deplete the mother’s bone density if she does not get adequate calcium through her diet and, if prescribed by her doctor, prenatal supplements. Because “megadosing” on calcium can lead to other problems, such as kidney stones, it is important to consult with a physician about appropriate intake of calcium and other nutrients. At this time, there are no treatments, or dietary supplements that can prevent the child from having OI or that will make the type of OI milder.
Genetic Counseling and Prenatal Diagnosis
It is recommended that couples at risk of having a child with OI seek genetic counseling before conception, or as early in the pregnancy as possible. A genetic counselor can provide information on OI genetics and prenatal diagnosis. Collagen testing of the parent with OI can be a useful tool to diagnose the child. Because collagen testing takes months to be completed, it should be initiated before conception if the person with OI has not been previously biopsied. A geneticist can also provide information about preimplantation genetic testing.
Preimplantation genetic testing or preimplantation genetic diagnosis is a new procedure that has recently become available. It involves in vitro fertilization plus the added step of “embryo analysis.” After a couple has gone through the initial stages for in vitro fertilization and embryos have been formed, a single cell is removed from the dividing cells at the 8-cell stage and is tested for a single genetic condition, in this case OI. If the embryo does not show any signs of OI, it is then implanted in the mother to continue normal development. At this time there is no known adverse effect on the fetus to having one cell removed at this stage. To be a candidate for this procedure, the parent’s exact genetic mutation must be identified, usually through a collagen biopsy or DNA analysis, and a mutation-specific test developed. This procedure cannot remove the OI gene (or the gene for any other condition), but only embryos without the mutation are implanted.
Undergoing prenatal diagnosis does not obligate parents to elect pregnancy termination, and the information may be useful in managing pregnancy and delivery. According to a recent study (Cubert), prenatal diagnosis did not influence mode of delivery in most instances.
Ultrasound can be used to examine the fetus’ skeleton for bowing, fractures, shortening, or other bone abnormalities consistent with OI. Ultrasound is generally most helpful for prenatal diagnosis of the more severe forms of OI. The fetal skeleton shows signs of OI as early as 16 weeks in OI Type II and 18 weeks in OI Type III. Fetuses with mild OI seldom show evidence of fractures or deformity before birth. Ultrasound is a noninvasive, low-risk procedure. There are different levels of ultrasound, some of which are more useful than others in detecting OI.
Chorionic villus sampling (CVS) and amniocentesis analyze cells obtained from the fetus for collagen defects and/or a genetic mutation that causes OI. CVS looks at placental cells, while amniocentesis examines fetal cells (amniocytes) shed into the amniotic fluid. Both of these procedures carry a risk of miscarriage (about 1 in 200 for amniocentesis, and about 1 percent for CVS). These prenatal tests are useful if the parent who has OI already has the results of his or her own collagen or DNA tests. For more information about these prenatal diagnostic procedures, consult a genetic counselor, and see the OI Foundation fact sheet titled OI Issues: Genetics.
Some physicians might consider a planned cesarean section if a woman has a history of pelvic fractures or contracted pelvis, if the woman has a severe form of OI, or if other significant complications are present. Some of the complications that have been reported during delivery include a birth canal that is too small to permit birth, uterine rupture, and hemorrhage. Women at greatest risk for bleeding are those with a history of recurrent nosebleeds, easy bruising, or excessive bleeding following previous surgical procedures. Though uterine rupture has been reported to occur (Carlson), it does not appear to be a frequent complication.
Because some people with OI may be at increased risk for hyperthermia (an increase in body temperature in response to anesthesia), some physicians might consider spinal or epidural anesthesia to be the safest approach. However, these anesthesia procedures, which involve injection of medication near the spine, may be difficult in some women with spinal curvature, deformity or compression fractures.
Planning for the delivery should also include conferring with the hospital’s neonatologist, chief obstetrical nurse and nursery staff. Medical personnel who have experience with premature infants often have the skills necessary to handle a tiny, fragile baby who has OI. Parents may also want to make arrangements, prior to the due date, to have cord blood saved for DNA analysis. It can be helpful for families at risk for OI Type I or Type IV to have the question of OI inheritance answered as soon as possible.
Cubert R, Cheng E, Mack S, Pepin MG, Byers PH, Osteogenesis Imperfecta: Mode of Delivery and Neonatal Outcome. Obstetrics & Gynecology, 2001;97.
DeVos A, Sermon K, Van de Velde H, Joris H, et al. Two pregnancies after Preimplantation Genetic Diagnosis for Osteogenesis Imperfecta Type I and Type IV. Human Genetics, 2000; 106: 605-13.
Krishnamoorthy U, Vausse S, Donnai P. Management of Pregnancy Complicated by Maternal Osteogenesis Imperfecta. Report of a Case with Uterine Rupture. Journal of Obstetrics and Gynaecology, 2002; 22: 316-322.
McAllion SJ, Paterson CR. Musculo-Skeletal Problems Associated with Pregnancy in Women with Osteogenesis Imperfecta. Journal of Obstetrics and Gynaecology, 2002; 22: 169-72.
Reed, Susan R. M.D., Women and OI: Survey Results Reveal OB/GYN Trends Vary by OI Type in Females. Breakthrough, January/February 2000, Osteogenesis Imperfecta Foundation.
Vogel TM, Tatner EF, Thomas RC Jr, Chitkara U. Pregnancy Complicated by Severe Osteogenesis Imperfecta: A Report of Two Cases. Anesthesia Analg, 2002; 94: 1315-7.
This information is brought to you by the National Institutes of Health The National Resource Center is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with contributions from the National Institute of Child Health and Human Development, National Institute of Dental and Craniofacial Research, National Institute of Environmental Health Sciences, NIH Office of Research on Women's Health, Office of Women's Health, PHS, and the National Institute on Aging. The Resource Center is operated by the National Osteoporosis Foundation, in collaboration with the Paget Foundation and the Osteogenesis Imperfecta Foundation.
This information is brought to you by the
National Institutes of Health
The National Resource Center is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with contributions from the National Institute of Child Health and Human Development, National Institute of Dental and Craniofacial Research, National Institute of Environmental Health Sciences, NIH Office of Research on Women's Health, Office of Women's Health, PHS, and the National Institute on Aging. The Resource Center is operated by the National Osteoporosis Foundation, in collaboration with the Paget Foundation and the Osteogenesis Imperfecta Foundation.