Is it normal to feel out of breath during pregnancy
Like heartburn, indigestion and constipation, shortness of breath is yet another delightful symptom that most women experience at some stage of their pregnancy. It is a common and harmless sign, occurring from normal body changes at the time .
Although you may be gasping for air after climbing up the stairs or walking from the car to your door, be assured that this is not bothering your baby in any way as the placenta is supplying him with enough oxygen .
Is shortness of breath an early sign of pregnancy
Although it may come pretty early during the first trimester in some women, the feeling of breathlessness is not considered an early pregnancy symptom as it can occur anytime during gestation.
What makes you short of breath in pregnancy
There may be different factors responsible for making it hard to breath in the three trimesters.
Early and mid-pregnancy causes
The increasing hormone levels, especially progesterone, induce the brain in the first or early second trimester, so you can take frequent deeper breaths to get enough oxygen for you and your growing baby . So, you take in considerably higher amounts of air with each breath, making you feel out of breath all the time . Additionally, the pregnancy hormones contribute to the breathing difficulty by causing the respiratory tract capillaries to swell while relaxing the lung and bronchial tube muscles .
During the later part of your second trimester, the growing uterus starts putting pressure on the diaphragm, leading to breathing problems, often accompanied by chest pain and heartburn . It is more common in twin pregnancies and women carrying the baby high .
Late pregnancy causes
By the later part of your third trimester, the growing uterus starts pushing all the other organs (including the lungs) away to make space for itself . The diaphragm moves up almost 4cm from its normal position , providing less space for the lungs to expand during inhalation, leading to rib pain and breathing problems .
How long does the breathlessness last during pregnancy
After weeks 35-36, your baby starts to drop down into the pelvis (engage) to get into the birth position. So, your breathlessness is likely to ease slightly as there is less pressure on the lungs and ribcage . However, the baby does not engage until the end of term in case of a second or subsequent pregnancy .
Following delivery, the breathlessness goes away on its own as the progesterone levels go down to normal, relieving the pressure on your lungs.
How to relieve breathing difficulty while pregnant
- Practicing proper posture, making sure to stand and sit up straight to give your lungs as much space as possible to expand 
- Using some pillows or cushions to keep yourself propped up while lying down or sleeping as it reduces the pressure on your lungs 
- Taking slow deep breaths through your mouth whenever you feel breathless
- Wearing loose clothes so you can breathe easily 
- Raising your arms slowly while inhaling and then bringing them down again when exhaling – this gives the lungs more space while taking in air by lifting the ribcage 
- Following a light exercise routine can help you remain fit, reducing the feeling of being out of breath all the time 
- Slowing down in whatever you are doing when you feel out of breath, taking a moment to catch your breath 
- Taking smaller meals to reduce the chances of experiencing shortness of breath after eating
- Joining a prenatal yoga class where you can learn various relaxation and breathing techniques
When to call the doctor with troubled breathing
- Shortness of breath along with palpitations, anxiety, confusion, dizziness, nausea, vomiting, blurred vision, lower back pain, persistent headache and sudden weight gain, especially in later pregnancy (might indicate high blood pressure or preeclampsia) 
- Breathing troubles accompanied by considerable fatigue, rapid heartbeat, lightheadedness and pale or bluish lips and fingertips (might indicate low iron levels or anemia) [16, 17]
- Breathlessness and chest pain when taking deep breaths along with an abnormally fast pulse (might indicate pulmonary embolism or blood clotting in lungs) 
- Excessive shortness of breath with severe cough (worsening during early morning or at night), tightness in chest and wheezing, especially in asthma patients (might indicate an aggravation of the condition) 
- http://www.nhs.uk/conditions/pregnancy-and-baby/pages/asthma-pregnant.aspx#close [/ref]