Being pregnant with twins is absolutely normal. And when you find out that you are pregnant with twins, it can be an exciting and at the same time a shocking situation There are certain differences between a regular pregnancy and a pregnancy with twins, so it is important to understand the different changes and stresses your body may experience and the best ways to handle your pregnancy.
Types of Twins
There are two types of twins – identical (monozygotic) and fraternal (dizygotic) twins.
Monozygotic twins are also known as identical twins, and this happens when one egg is fertilized by one sperm, but then divides into two separate embryos.
Dizygotic twins are known as non-identical or fraternal twins, and this occurs when two separate eggs are fertilized by two different sperm.
Causes of Pregnancy with Twins
Your chances of having twins are increased by having a family history of twins, being older when you get pregnant, intake of folic acid supplements before getting pregnant, having a certain ethnic background, and having a higher BMI, among others.
The older you are when you conceive, the better chance you have of getting pregnant with twins. As women age, and approach menopause, they might begin to release more than one egg at the same time, which can make non-identical twins far more likely. This is caused by a surge in estrogen as women approach menopause. 
There appears to be a mild genetic cause to having twins, and if someone on your mother’s side has had twins in the past, you have a better chance of conceiving twins. 
Folic Acid Supplements
All doctors recommend folic acid supplementation during pregnancy to ensure normal growth and development, but if you also take folic acid supplements before you get pregnant, this will tell the body that it can support more than one embryo and thus increase your chances of becoming pregnant with twins.  
Research has found that women of African descent have a much higher level of twin births than women from other ethnic backgrounds. 
If you are slightly heavier or larger, you have a better chance of conceiving twins. When your body has ample nutrients, this is a signal that you are capable of safely supporting more than one embryo, leading to a better chance of twins developing. 
Symptoms of Being Pregnant with Twins
There are a number of clear symptoms that you may be pregnant with twins, including weight gain, rapid uterine stretching, exhaustion, and persistent morning sickness, among others.
While gaining weight is a natural part of pregnancy, thanks to the extra human being inside your body, women who are pregnant with multiples often gain an average of 10 pounds more than they would in a normal pregnancy, which is a strong hint that you are eating for three! 
There are certain physical exams that can be performed by doctors to measure your pregnancy progression. The stretching of your uterus and the distance between your pubic bone and uterus will be indicative of your body preparing to carry more than one infant, even early in the pregnancy.
Being pregnant can tire anyone out, but if you are experiencing extreme fatigue and weakness, it could be due to a pregnancy with twins. When a mother is attempting to support the development of two embryos, it can be a major drain on her nutrients and resources, leading to frequent feelings of weakness. 
Morning sickness is something that affects almost all pregnant women, but if your morning sickness lasts for months, or happens very frequently, it may be due to the even larger hormonal spike that happens when you are carrying twins.
Tests for Twin Pregnancy
While some of the signs and symptoms above may suggest that you are pregnant with twins, the only sure sign is to undergo certain tests by doctors, including ultrasounds, heartbeat measurements, and high Human Chorionic Gonadotropin (hCG) levels.
Ultrasound – An ultrasound is a most reliable and most common way to visually see the inside of the womb, where it is easier to detect the presence of two growing embryos. 
Heartbeat Test – Another popular test is a Doppler heartbeat test, typically near the end of the first trimester. At this point, it can be possible to detect multiple heartbeats, but this isn’t a widely reliable test, and should not be trusted as 100% accurate.
HCG Levels – When the embryo binds to the uterus wall, it begins to release Human Chorionic gonadotropin (hCG), which can be detected in both urine and blood tests. However, like a heartbeat test, levels of hCG may be elevated for other reasons, so this isn’t a 100% accurate means of determining whether you are carrying multiples. 
Complications of Being Pregnant With Twins
There are a few common complications of being pregnant with twins, such as a higher risk of miscarriage, preterm delivery, birth defects and gestational hypertension, among others.
Miscarriage – In some cases, following the positive determination of a twin birth, one of the fetuses will “vanish” and be miscarried at some point in the term. There is a higher risk of this type of miscarriage than a typical miscarriage in a single-fetus scenario. 
Pre-Term Delivery – It is very common for multiples to be born premature; in fact, more than 60% of multiple pregnancies are delivered prematurely. While this can be dangerous, as some of their organs may not be fully developed, since this is such a common occurrence, doctors are more than prepared to ensure a safe delivery, even if it happens before 37 weeks. 
Birth Defects – There is a much higher chance of birth defects in multiple births; this may be due to the fact that more fetuses are competing for critical nutrients, and if there is a deficiency for either of the children, it can result in defects like spina bifida and congenital heart defects. 
Gestational Hypertension – When carrying twins, expecting mothers are at much higher risk for gestational hypertension. In fact, you are more than twice as likely to experience high blood pressure during your pregnancy if you are carrying twins, which also raises your risk of preeclampsia and abduction – when the placenta detaches from the wall of the uterus. 
Anemia – Women are 50% more likely to suffer from anemia during pregnancy if they are carrying twins; this can lead to poor nutrient absorption and a host of other side effects, both for the mother and the unborn child. Iron supplements, along with many other dietary boosters, are recommended for women carrying multiples.