There is no joy and delight like expecting a baby and even double the joy when you are pregnant with twins or multiple babies. They look so adorable together and alike that sometimes you may even have a hard time telling them apart. But what exactly are twins or multiple births? How many types of twin are there? Or what are the factors that increase your chance of a multiple pregnancy? Here is everything you need to know about your precious pair. Let’s begin.
1. What Are Twins or Triplets?
If you are pregnant with more than 2 or more fetuses (developing babies), it is called a multiple pregnancy, with two fetuses called “twins”, three called “triplets”, four fetuses called quadruplets, etc. Carrying more than two or three fetuses is often called, “high-order multiples”.
2. How Many Types of Twins Are There?
There are two basic types of twins;
2.1 Fraternal Twins
“Fraternal twins.” In this twin type, instead of one egg, a woman’s ovaries release two eggs (ova) at the time of ovulation and each is fertilized by a separate sperm. The two embryos implant in the lining of your uterus, and develop into two fetuses in your uterus at the same time.
Because fraternal twins are the result of different eggs and different sperm, they don’t look exactly alike and can be the same or different sexes. Fraternal twins, therefore, sometimes are also called, “non-identical twins” or “dizygotic twins,” which mean “two-cell” or “deriving from two separate ova”
2.2 Identical Twins
The second type, “identical twins” or “monozygotic (one-cell) twins”, are conceived from one fertilized egg that divides into two embryos during the cell division stage. After splitting in two, the self-contained halves then develop into two fetuses with exactly the same genetic information, resulting in twins who are the same sex and identical looking.
3. What Factors Increase the Chance of Having Twins or Multiple Pregnancies?
Some women are more likely than others to give birth to twins. According to the American Society for Reproductive Medicine or ASRM, the most common factors include race, age, heredity, history of prior pregnancy, as well as the use of fertility drugs or Assisted Reproductive Technology.
However, according to ASRM, “your race, age, heredity, or history of prior pregnancy does not increase your chance of having identical twins but does increase your chance of having fraternal twins,” while fertility drugs and assisted reproductive technology can increases your risk of having either type of twins, both identical and fraternal.”
- Race: Studies show that women from South-East Asia, and women of Hispanic origin are substantially less likely to have twins than non-Hispanic Whites and African origin mothers.
- Heredity: Both mother’s and father’s family history play a crucial role in increasing the odds. However, according to ASRM, “The mother’s family history may be more significant than the father’s.” Moreover, a mother will increase her odds of having twins or multiple pregnancy if her sister, her mother, or her mother’s mother had fraternal twins or she herself is one of the fraternal twins.
- Maternal Age: Studies have shown that the likelihood of twins increases with age. In a study of pregnant women who are over 45 years old, 16% of them had multiple pregnancies, with twins being the highest percentage. Moreover women in their 30s or 40s tend to have higher levels of oestrogen which make their ovaries ovulate more than one egg at a time.
- Prior Pregnancy History: The more times a woman has become pregnant, especially pregnant with 2 or more babies, the more likely she is to have twins or multiple pregnancies.
- Fertility Drugs: The use of fertility drugs, particularly ovulation-stimulating medications often used to help stimulate and produce many eggs, can play a role in increasing the odds of having multiple babies.
- Assisted Reproductive Technology: The use of Assisted Reproductive Technology (ART) procedures such as In Vitro Fertilization (IVF) is also generally found to contribute to an increase in multiple birth rates in cases where a higher the number of embryos are transferred back into the woman’s uterus.
4. What Are the Complications and Risks Associated with Multiple Pregnancies?
While expecting twins or multiple births can be a marvelous and exciting time, multiple pregnancies also carry a higher risk of complications. The most common problems include:
4.1 Preterm labor and birth: 60% of twins and almost all high-order multiples are premature babies (born before 37 weeks). The greater the number of fetuses pregnant, the greater the risk of premature delivery. Preterm delivery can cause an infant to need help in breathing, eating, fighting infection, and staying warm, and thus cause him or her to be specially cared for in a neonatal intensive care unit (NICU) until she or he is strong enough to survive on his or her own.
4.2 Gestational hypertension: Referred to as Pregnancy-Induced Hypertension (PIH), gestational hypertension is a condition characterized by high blood pressure during pregnancy that can lead to serious complications for both mom and babies if not treated quickly.
4.3 Anemia: All expecting mothers generally become anemic, but when you are expecting twins, chances are that you will be more anemic and extremely tired compared to mothers with a singleton pregnancy.
4.4 Birth defects: Multiple babies are roughly twice as likely to have difficulties that are present at birth (congenital), such as spina bifida and other neural tube disorders, as well as digestive and cardiovascular issues. Note that even with these increases, the risks are still low.
4.5 Miscarriage: In multiple pregnancies there can be a condition called “Vanishing Twin Syndrome”. In this unfortunate condition, more than one fetus is found after the ultrasound, but during the pregnancy one of the fetuses vanishes (or is miscarried).
4.6 Twin-to-twin transfusion syndrome: Also called “TTTS,” this rare yet severe pregnancy condition refers to a situation where the twins share one placenta and a network of blood vessels that supply oxygen and nutrients essential for development in the womb, but for some unfortunate reasons, the vessel connections within the placenta are not evenly distributed, and the blood exchange between the twins is unbalanced, causing one twin to give away more blood and being put at risk of malnutrition, organ failure and, if not treated quickly and properly, eventual intrauterine death.
5. What Can I Do If I Want to Have Twins?
As discussed in the factors section, a person’s chance of having twins are quite arbitrary and complicated. There’s no perfect or exact recipe for you to try to have twins as each individual’s physical condition and personal history varies. What you can do surely and safely, however, is discuss your health and physical condition with your trusted and reliable doctor or experienced healthcare provider, and assess your odds of having twins Also, if you think that you may have higher chance of having twins with Assisted Reproductive Technology procedures like ICSI, IUI and IVF, it is important that you carefully select a fertility clinic that is truly ethical and experienced to avoid serious risks and complications commonly found in these advanced procedures.
About Superior A.R.T.
Superior A.R.T offers comprehensive fertility and genetic services in state-of-the-art Assisted Reproduction Technology (A.R.T.) Laboratories in Bangkok Thailand. Superior A.R.T. was founded in 2007 by a group of leading Thai Infertility specialists in collaboration with Australian world-leading fertility and A.R.T. treatment providers, Superior A.R.T is a renowned fertility clinic offering comprehensive fertility and genetic services by a team of experienced treatment providers and researchers specifically specializing in Assisted Reproduction Technology – A.R.T. Superior A.R.T. is committed to making your dream of having a healthy baby come true.
The Importance of Sex Selection in Embryos in The Prevention of Genetic Disorders
Some severe genetic disorders are sex-linked, that is they are due to disorders of either the X or the Y chromosomes. Sex selection, often wrongly termed gender selection, is not only ethical and legal but could also, in many cases,
What is ICSI? How Is It Different from IVF?
Intracytoplasmic Sperm Injection, more commonly referred as ICSI, is potent fertilization method used in the In Vitro Fertilization (IVF) process. The only difference between standard IVF and ICSI is in the method used to allow the sperm to fertilize the egg. This adjunct procedure has helped millions of couples overcome their infertility issues.