The risks of any congenital defects drop dramatically once you reach the 10th week of your pregnancy as the most vital stage of fetal development is over . Although it does not mean that you and the baby are safe from any complications in the coming months, following the guidelines of your ob-gyn can help you have a healthy pregnancy from this stage.
Pregnancy week 10: fetal development
Sensory Organ Development
Development of the eyes continues with the main optical structure already being in place . The external ears have completed their growth while the internal ear is almost done growing as well. Both the eyes and ears start developing at the sides of the head, later moving to the right place.
The forehead starts bulging up at this stage, sitting high on the head while the hair follicles begin to grow as well. The fetal head will soon appear normal as the forehead gradually flattens .
The thin hands and legs continue to grow longer while the fingers and toes start to grow nails and unique finger prints . The bones and cartilages also keep growing during the 10th week .
Nervous System Development
The outline of the spine becomes clearly visible at this stage with the spinal nerves stretching out from it .
Internal Organ Development
The vital organs of your baby, including the brain, liver and kidneys begin to function on their own while continuing their growth at the same time . The intestines are already hollow tubes with muscles that help them move and tighten , helping your baby to practice swallowing.
This is also the week when the diaphragm begins to develop, gradually separating the chest and abdomen. The sex organs also grow rapidly and you will soon be able to know whether to paint the nursery blue or pink .
10 weeks pregnancy baby size
The fetus that was the size of a green olive is now a big as a lime with his crown to rump measurement being around 1.2 inches  (3.1 cm). He has also started gaining weight, currently weighing about 0.14 ounces (4g) .
Body changes during week 10 of pregnancy
Your growing uterus and increasing blood volume continue to lead to certain pregnancy pains and other symptoms. The high pregnancy hormone (HCG and progesterone) levels make your complexion smoother and shinier, giving you the well-known “pregnancy glow” by increasing the number of facial oil glands . The growing milk-producing glands may also lead to fuller breasts .
What does 10 weeks pregnant look like?
Although you might notice your belly expanding quite a bit in the past few weeks, it is still too early for others to start noticing your baby bump . However, there is nothing to worry about if you do not start showing at all at this stage, especially if this is your first pregnancy .
10 weeks pregnant ultrasound
An ultrasound scan performed this week shows the head to comprise about half the length of your baby  with some fuzzy hair growth .
The translucent or see-through skin allows you to see the functioning of the inner organs on a 4D ultrasound . This is usually the week when the parents hear their child’s heartbeat for the first time, which is often described as being similar to the sound of galloping horses .
Prenatal testing during pregnancy week 10
Your doctor may ask you to take certain genetic tests at this stage to detect any hereditary or congenital disorders like Down syndrome . All these tests are non-invasive, meaning only a few blood samples are collected from you to examine your baby’s DNA. Some of these tests are performed routinely during your prenatal checkups while others are only necessary in high risk cases (having a family history of some genetic disorder or being over 35 years of age) 
Pregnancy symptoms at 10 weeks
In many women, the symptoms of morning sickness, dizziness and headache begin to subside in the tenth week . But, there is nothing to worry about if the symptoms persist. Apart from heartburn, bloating and flatulence, the common symptoms experienced during the tenth week include:
- Mild abdominal pain 
- Lower back and pelvic pain
- Round ligament pain 
- Tiredness and fatigue
- Sleep disturbances (insomnia)
- Having unusual dreams 
- Rapid emotional changes and depression 
- Bluish prominent veins mainly around the breasts and belly (due to increased blood flow) 
- Breast changes
- Abdominal and breast tenderness 
- Rapid weight gain 
- Acne outbreak
- Excessive hunger and thirst
- Shortness of breath
- Constipation (due to pregnancy hormones and the expanding uterus) 
- Joint pain
When to call the doctor?
The chances of miscarriage drop considerably after the 10th week. However, it is advisable to look out for the following symptoms to avoid serious complications:
- Extreme nausea, vomiting and throwing up chunks of blood (leaving these symptoms unattended might hurt the baby, causing dehydration and weight loss) 
- Severe abdominal cramping and/or heavy vaginal bleeding (might indicate an ectopic pregnancy or miscarriage) 
- Extreme pelvic or groin pain
- Pain or burning sensation while urinating (might indicate infections like UTI and cystitis) 
- Brown discharge
- Odd smelling clear, yellowish or greenish cervical mucus (might indicate an infection like yeast infection)
- Fever (over 102 °F) and chills (might increase the risk of miscarriage)
- Extreme headache with or without dizziness and fainting 
Tips for a healthy pregnancy and baby
- Include plenty of protein-rich foods in your daily diet. Fresh vegetables like beans and lentils, nuts, soy products, fish and meat are some safe sources of healthy protein 
- Sipping some ginger ale or nibbling on a few salty crackers before getting out of bed in the morning can help to reduce nausea and vomiting
- Drinking plenty of fluids to stay hydrated; fruits with high water content, such as melons, also prevent dehydration
- Increasing your calcium intake (necessary for the baby’s growing bones and teeth) 
- Eating small healthy snacks throughout the day to avoid staying on an empty stomach (helps to manage nausea) 
- Avoiding greasy or fatty foods to prevent too much weight gain (you only need to gain 300 extra calories, 600 if expecting twins, throughout the pregnancy) 
- Taking your multivitamins and folic acid supplements regularly
- Going for a dental checkup (as the changing blood volume might cause bleeding or swollen gums) 
- Doing light exercises (like walking) or joining a prenatal yoga class 
- Asking your partner to come with you on your next prenatal checkup so he can better understand what you are going through from this early stage; it also helps to form a bond between him and the baby
- Shopping for maternity clothing (you will soon need them)
- http://www.whattoexpect.com/pregnancy/eating-well/week-10/smooth-moves.aspx# [/ref]