The first month, there is yang energy. ☰ Qián trigram is yang energy and also means "Heaven". The highest (high in heaven) part of the body, the head is formed.
The 2nd month, the yang energy slowly produces a lake of liquid. This relates to the 2nd trigram in the Early Heaven Bagua Sequence - ☱ Duì. This trigram is also known as "Lake". The fetus' lungs are formed in this month. Indeed the lungs are very moist. Wet. Therefore represented by the lake.
The 3rd month, the yang energy combining with the 'lake' becomes hot. This is connected to the next trigram. ☲ Lí trigram translates into "Fire". The heart is formed in the 3rd month. In the study of Yijing, the heart is related to fire element.
In the 4th month, the fetus is able to start moving. This is the ☳ Zhèn trigram. This trigram symbolizes "Thunder" or movement. Think about the lightning which causes the thunder. It moves with much energy. The liver is formed.
In the 5th month, the movement has brought breathing. Thus we see the following trigram ☴ Xùn. Also symbolizes "Wind". The gall is formed.
In the 6th month, the water in the womb flourishes. This relates to ☵ Kǎn trigram. Also symbolizes "Water". The kidneys are formed. Indeed kidneys are closely related to water because they are an essential part of the urinary system.
In the 7th month, intestines and stomach are formed. This relates to ☶ Gèn trigram. The symbol for "Mountain". In the study of Yijing, Gen trigram is earth element. Earth being the storage of minerals, so is the stomach as a storage of food.
In the 8th month, the flesh is fully developed. Finally, we see the trigram ☷ Kūn. This trigram symbolizes "Earth". Some religious scriptures mention that humans were made from earth. The Chinese baby is now ready to be born on the 9th month.
That's the complete pregnancy cycle and how it relates to the Yijing and Bagua sequence. You can see now why Yijing is very important in selecting the name. The connection it has with us is truly profound.