Planning a pregnancy

What does carrier mean?

Some conditions appear only if both copies of a gene are changed. A person with only one changed copy is called a carrier. A carrier is usually healthy. Most people do not know they are carriers. When two carriers have a child together, the child may be affected. A carrier test shows whether a person carries this kind of change.

Source: MedlinePlus Genetics – What are the different types of genetic tests? · HSGM – Evlilik Öncesi Hemoglobinopati Tarama Programı

The chance is the same in every pregnancy

The chance depends on how the condition is inherited. These figures apply to each pregnancy separately. Whether an earlier child is affected or healthy does not change them.

1. If both mother and father are carriers: in each pregnancy, the chance that the child will be affected is 25 percent. The chance that the child will be a carrier is 50 percent.
2. If the condition appears with a single copy (dominant inheritance): the chance of an affected parent passing it to a child is 50 percent in each pregnancy.
3. In X-linked recessive inheritance: for a carrier mother, the chance that a son will be affected is 50 percent in each pregnancy.

Source: MedlinePlus Genetics – If a genetic disorder runs in my family, what are the chances that my children will have the condition? · HSGM – Evlilik Öncesi SMA Taşıyıcı Tarama Programı

Sometimes the change is new

In some children, the gene change does not come from the mother or the father. The change appears for the first time in that child. This is called a new (de novo) change. In this case, the chance for brothers and sisters may be different. Working out your family’s chances can be complicated. You can discuss this in genetic counseling.

Source: MedlinePlus Genetics – If a genetic disorder runs in my family, what are the chances that my children will have the condition?

Genetic counseling before pregnancy

Genetic counseling helps you understand your own chances and options. Talking before you plan a pregnancy gives you more time. Even if you choose not to be tested, you will continue to receive care and support. For details, see the genetic counseling section of the “Newly diagnosed: first steps” guide.

Source: NHS – Genetic and genomic testing · MedlinePlus Genetics – If a genetic disorder runs in my family, what are the chances that my children will have the condition?

Hemoglobinopathy and SMA screening

Couples who apply to their family doctor for a marriage health report are screened for inherited blood disorders and SMA. Blood is first taken from the male partner. If carrier status is suspected, a sample is also taken from the female partner. Married couples who want to have children can also ask for SMA screening. The programs are described in detail in the “Newly diagnosed: first steps” guide.

Source: HSGM – Evlilik Öncesi Hemoglobinopati Tarama Programı · HSGM – Evlilik Öncesi SMA Taşıyıcı Tarama Programı

If you are both carriers

According to the Sağlık Bakanlığı (Ministry of Health) pages, couples who are both carriers are referred for genetic counseling. The couple is given detailed information. For SMA, prenatal diagnosis and genetic testing of embryos are offered, after counseling, to families who want them. Being a carrier does not in itself decide whether to marry or whether to have children. These decisions belong to the couple.

Source: HSGM – Evlilik Öncesi Hemoglobinopati Tarama Programı · HSGM – Evlilik Öncesi SMA Taşıyıcı Tarama Programı

Consanguineous marriage: non-judgmental information

Partners who are related may carry the same gene change. This is why the chance of recessive conditions may be higher. In a 2013 national survey by the Ministry of Health, about one in five married women were in a consanguineous marriage. Specialists recommend taking a detailed family history for these couples. The same screenings can also be offered during pregnancy. Being related does not mean that every child will be affected.

Source: Kaplan ve ark. Türkiye'de akraba evliliği sıklığı, ulusal araştırma, J Biosoc Sci 2016 (PubMed 26892044) · Hiz Kurul ve ark. Akraba evliliği olan ailelerde trio ekzom, Brain 2022 (PubMed 34791078) · Bennett ve ark. NSGC önerileri, J Genet Couns 2002 (PubMed 26141656)

A screening test is different from a diagnostic test

A screening test only gives a probability. It does not give a definite result. A diagnostic test looks directly at cells that come from the baby. Prenatal tests cannot find every inherited condition or congenital problem. You can ask your doctor which test looks for the condition in your family.

Source: MedlinePlus Genetics – What are the different types of genetic tests? · MedlinePlus Genetics – What is noninvasive prenatal testing (NIPT)?

Cell-free DNA test (NIPT) and its limits

NIPT is a screening test done on the mother’s blood. It looks at pieces of DNA in the blood that come from the placenta. It mainly looks for differences in chromosome number, such as Down syndrome. It can give a false “high chance” or a false “low chance” result. A high-chance result is confirmed with a diagnostic test. Its use for single-gene conditions is new and limited.

Source: MedlinePlus Genetics – What is noninvasive prenatal testing (NIPT)?

Chorionic villus sampling (CVS)

In CVS, a small sample of tissue is taken from the placenta. Usually a thin needle is passed through the abdomen. According to the NHS, it is usually done between weeks 11 and 14 of pregnancy. The Ministry of Health SMA page mentions week 10. The NHS gives the risk of miscarriage as less than 1 in 200 in most pregnancies. Having it is not compulsory.

Source: NHS – Chorionic villus sampling (CVS) · HSGM – Evlilik Öncesi SMA Taşıyıcı Tarama Programı

Amniocentesis

In amniocentesis, a sample is taken from the fluid around the baby. The needle is passed through the abdomen, guided by ultrasound. According to the NHS, it is usually done between weeks 15 and 20. The risk of miscarriage is about 1 in 200 pregnancies. Some results come within a few days, others in about two weeks. This test is also optional.

Source: NHS – Amniocentesis · HSGM – Evlilik Öncesi SMA Taşıyıcı Tarama Programı

After the result

When the result is ready, your doctor explains what it means for your baby and for you. Some families use this information to prepare for the birth and for care. Some families consider whether to continue the pregnancy. Whatever path you choose, you have the right to information and support. The legal framework in Türkiye is described in a separate section below.

Source: NHS – Amniocentesis · MedlinePlus Genetics – What are the different types of genetic tests?

What is PGT?

In IVF, eggs and sperm are joined in the laboratory. A few cells are taken from each embryo and tested. Only embryos that do not carry the change being looked for are placed in the womb. Because the embryo has to be tested, IVF is needed even if the couple has no problem having children.

Source: MedlinePlus Genetics – What are the different types of genetic tests? · HFEA (Birleşik Krallık) – PGT-M ve PGT-SR

The limits of PGT

PGT is not completely accurate. Sometimes there is no suitable embryo to place in the womb. Success depends on many factors, such as the woman’s age. IVF itself also has risks. You can discuss these issues with your doctor before treatment.

Source: HFEA (Birleşik Krallık) – PGT-M ve PGT-SR

IVF rules in Türkiye

In Türkiye, IVF is only offered to married couples (Regulation, Art. 19(2)). Only the couple’s own eggs and sperm may be used. Using a donor is prohibited (Regulation, Annex 17). A couple’s embryo cannot be placed in another woman. The child’s sex cannot be chosen. The only exception is to avoid a serious sex-linked inherited disease (Annex 17).

Source: Üremeye Yardımcı Tedavi Uygulamaları ve Üremeye Yardımcı Tedavi Merkezleri Hakkında Yönetmelik (RG 30.09.2014/29135) (mevzuat.gov.tr) · ÜYTE Yönetmeliği ekleri, Ek-8 ve Ek-17 (Resmî Gazete 30.09.2014/29135)

Consent form, number of embryos and storage

Before treatment, the couple signs an informed consent form together (Art. 19(2), Annex 8). The form is given one day before treatment and is also read aloud. The number of embryos that can be transferred is limited according to age and the number of attempts (Annex 17). Extra embryos can be frozen with the consent of both partners (Art. 20(5)). If storage lasts more than one year, the couple applies in writing every year.

Source: Üremeye Yardımcı Tedavi Uygulamaları ve Üremeye Yardımcı Tedavi Merkezleri Hakkında Yönetmelik (RG 30.09.2014/29135) (mevzuat.gov.tr) · ÜYTE Yönetmeliği ekleri, Ek-8 ve Ek-17 (Resmî Gazete 30.09.2014/29135)

General IVF payment (SUT 2.4.4.İ-1)

SGK pays for up to three attempts for couples who meet the conditions. Under this article, all the conditions must be met together. In some cases a co-payment is also charged (SUT 1.8.4).

1. Being married and having no child from this marriage (adopted children are not counted).
2. A medical board report showing that other treatments have not resulted in a child.
3. The woman being older than 23 and younger than 40.
4. The center having a contract with SGK.
5. One of the partners having been insured under general health insurance, or a dependant, for at least five years, with 900 days of premium payments.
6. No result having been obtained from other treatments in the last three years (not required for some diagnoses).

Source: SGK Sağlık Uygulama Tebliği (SUT), md. 2.4.4.İ (mevzuat.gov.tr)

PGT for a healthy child (SUT 2.4.4.İ-3)

If the condition is on the EK-2/K list annexed to the SUT, IVF with PGT may be paid for a married couple documented as affected or as carriers. Couples who already have a healthy child from this marriage are not covered. The age, contracted center and insurance period conditions also apply here. The report is issued by a medical board at a contracted tertiary public hospital. A genetic counseling note signed by a medical genetics specialist is required. The entitlement is up to three attempts.

Source: SGK Sağlık Uygulama Tebliği (SUT), md. 2.4.4.İ (mevzuat.gov.tr)

A sibling as a stem cell donor (SUT 2.4.4.İ-2)

If an affected child cannot be treated any other way and needs a stem cell transplant, IVF with PGT may be paid for to have a suitable donor sibling. This requires a medical board report on behalf of the child, with a genetics specialist on the board. The report is issued by certain hospitals that have a bone marrow transplant center. In this case, the general IVF conditions do not apply. Under the SUT, PGT is not paid for outside these two situations.

Source: SGK Sağlık Uygulama Tebliği (SUT), md. 2.4.4.İ (mevzuat.gov.tr)

The general framework of the law (Art. 2)

Under the law, population planning means that people can have as many children as they want, when they want. Ending a pregnancy is done under the supervision and oversight of the state. Outside the situations listed in the law, a pregnancy cannot be ended.

Source: 2827 sayılı Nüfus Planlaması Hakkında Kanun (mevzuat.gov.tr)

In which situations? (Art. 5)

Until the end of the tenth week of pregnancy, the uterus may be evacuated on request if there is no medical reason against it for the mother’s health. After ten weeks, this is only possible in certain situations. These are when the pregnancy threatens the mother’s life or would cause a severe disability in the child to be born. In this case, a reasoned report from an obstetrician-gynecologist and a specialist in the relevant field is required.

Source: 2827 sayılı Nüfus Planlaması Hakkında Kanun (mevzuat.gov.tr)

Whose permission is needed? (Art. 6)

The procedure requires the pregnant woman’s permission. If the woman is a minor, her own consent and the permission of her parent or guardian are required. For some people under guardianship, the permission of a justice of the peace (sulh hâkimi) is also required. For a procedure done on request before the tenth week, if the woman is married, her husband’s consent is also required. In life-threatening emergencies, no permission is required.

Source: 2827 sayılı Nüfus Planlaması Hakkında Kanun (mevzuat.gov.tr)

Options side by side

Some couples consider conceiving naturally and having tests during pregnancy. Some look into PGT with IVF. Some choose not to have testing. According to the Ministry of Health, these tests are done, after counseling, for families who want them. You can discuss which options are open to you with your medical genetics doctor and your obstetrician-gynecologist.

Source: MedlinePlus Genetics – What are the different types of genetic tests? · HSGM – Evlilik Öncesi SMA Taşıyıcı Tarama Programı · NHS – Genetic and genomic testing

Emotional support

Thinking about these issues can be exhausting. A genetic counselor can refer you to support groups. For sources of support, see the “Newly diagnosed: first steps” and “Rights and support” guides.

Source: NHS – Genetic and genomic testing · NHS – Amniocentesis