育児日記はbaby journalやbaby diaryといいます。
ちなみに妊娠中につける日記は、pregnancy journal/diaryと呼ばれています。
I keep my baby journal to track my daughter's growth/development.（育児日記をつけて娘の成長を追って記録しています）
I add some photos of her.（娘の写真を追加しています）
I keep track of my babies milestones by writing what they were on the back of a picture of them once a month.
A babies "milestones" are a list of achievements and abilities that they gain as they grow older.
Examples of a babies milestones would be eating solid food, sitting up, crawling, climbing up on objects, walking, talking, etc.
I am documenting my baby's growth.
The pictures you have taken and the written information you have are types of documenting to ensure that the information is not lost.
I am tracking my baby's growth and development.
This means you are attempting to track patterns and to closely monitor the rate at which your baby is growing and their pace of learning,
I am documenting my baby's growth.
The pictures you have taken and the written information you have are types of documenting to ensure that the information is not lost.
Documenting＝記録している。「私はベイビーの成長を記録しています。」子供の写真や日記に書いてある情報が消えないように記録している。
I am tracking my baby's growth and development.
This means you are attempting to track patterns and to closely monitor the rate at which your baby is growing and their pace of learning,
Tracking＝追跡する、追っている。「私はベイビーの成長と発達を追っています。」赤ちゃんの成長過程や学習速度をよく観察し、行動パターンなどを記録している。どちらも、育児日記をつける、とうニュアンスです。
I keep track of my daughter milestones/development in a book.
"I have a baby journal for my daughter."
This explains that you have a book which you write in for your daughter.
"Baby Journal" is a baby book.
"I keep track."
Means you keep note of /remember something by writing it down.
"Milestone or development"
Milestones are things your baby achieves or does.
These could be things like a first smile or new weight.
"I have a baby journal for my daughter."
娘のために育児日記をつけています。
娘のために日記をつけていると説明しています。
"Baby Journal" は育児日記です。
"I keep track."
記録をつける。
書くことで記憶にとどめようと記録すること。
"Milestone or development"
達成。Milestones 達成するという意味。
初めてのスマイルや体重など。
I keep a photo diary and log of all the development details of my baby
I update my baby's scrapbook regularly with all the changes
I have a baby milestones book
A log = an official record of events, especially during the voyage of a ship or aircraft.
"A ship's log."
Scrapbook = a book of blank pages for sticking cuttings, drawings, or pictures in.
There are actually books specially made for the purpose of recording baby's growth, development and inserting photos showing physical advancement and this is called: 'A milestones book.'
A log =イベントなどの公式なレコード、特に航海などを指すことが多い
"A ship's log."航海日誌
Scrapbook とは、絵日記や新聞を切り抜いたものなどを張り付けて保管している本
子供の成長を付ける用の本も実はあります。A milestone bookと言いますね。
I have a baby journal where I put all the photos of her/him growing!
A scrapbook: is a term used for a book with white pages that people stick pictures on and write in. Usually people make them better by putting postcards or receipts or drawings. Scrapbooks come in different shapes and forms and are very fun to use.
Journal: means that you are logging in your baby's growth and development but not necessarily with pictures.
Hope this helps!
A scrapbook（スクラップブック）: 白いページの帳面で、写真を貼り付けたり何かを書いたりします。絵やレシート、はがきを貼り付ける人が多いです。「scrapbook」にはいろいろな形があって、楽しいです。
Journal（日記）: 赤ちゃんの成長を記録することですが、必ずしも写真を使うわけではありません。
参考になるといいです！
"Scrapt Book" is a book you make of a special or dear occasion to you. Most people make a scrapt book of best friends, a loved one etc to include your baby's related activities.
"Baby Journal"this phrase is very specific to what you are doing. This baby journal can include many things from pictures to maybe the first diaper cream you used and other things. It is specifically for your baby.
日本 
カナダ 
南アフリカ 
イギリス 
アメリカ合衆国 
