Layover in Istanbul with infants

I would have expected you to have posted an answer from personal experience by now but instead Tavport.com has details of baby care rooms in Lounges: >

International Terminal

"primeclass" Lounge

Designed in plain and sophisticated style, the Lounge offers ultimate comfort 24/7 with facilities including self-service buffet options of fresh and tasty complimentary snacks, kids room, internet Access, Playstation, TV, tablet computers, newspapers and magazines, shower rooms and personal care products.

Location: One floor below the Food Court after the passport control point at the International Terminal Departures Floor

Turkish Airlines Lounge Istanbul Departure

Ranked as one of the world’s top ten private passenger lounges, “ Lounge Istanbul Departure” with a covered area of 6000 square meters, and capable of seating 1,100 people. The lounge provides unique tastes of Turkish and World dishes not found in other airline lounges.The lounge, where the modern is blended with the traditional, offers a set of atmospheres both tranquil and filled with entertainment to suit your desires. A great range of services and activities— including a realistic racetrack providing the excitement of a car race, video game consoles, a cutting-edge golf simulator, private resting and showering areas, media wall, cinema, a play area for children, a library, a pool room, a prayer room, a teleconference hall, and massage service—are at arm’s reach.

Turkish Airlines Lounge Istanbul Arrival

The lounge occupies a 300 square-meter area and provides seating capacity for 350 people. The lounge provides many services such us library, an always-current local and international magazine and newspaper section, Wi-Fi connectivity, and media walls, power outlets for your electronic devices. Also awaiting you at the Lounge Istanbul Arrival are relaxation areas equipped with shower stalls, a changing room, and an ironing room with staff to tend to your clothes that need ironing. The lounge accepts passengers from 5:00 a.m. to 12:30 p.m. local time and operates from 5:00 a.m. to 1:00 p.m.

Comfort Lounge

Open 24/7, the Lounge offers tasty snacks buffet and facilities including music system with personal headphones, wireless internet access, tablet computers, TV, daily newspapers, monthly and weekly magazines to ensure that passengers can relax and enjoy the time before their flights. In addition, showers and massage chairs are also offered in the Lounge for that ultimate comfort.

Location: Mezzanine floor after the passport control point at International Terminal Departures Floor within Istanbul Atatürk Airport.

SkyTeam Lounge

Operated by TAV “primeclass” CIP Service, SkyTeam Lounge adds value to the travel experience of Elite Plus, First and Business class passengers of SkyTeam Member Airlines with the services it offers 24/7. The business center of the 350 square meter Lounge which can accommodate up to 90 passengers at a time, is equipped with facilities including Wi-Fi access and printer and the eating section presents an open buffet service. The Lounge has more than 70 electric power sockets, a reading area and a separate TV room.

Location: Next to Gate 223 after the passport control point at the Istanbul Atatürk Airport International Terminal.

Emirates Lounge

Operated by TAV “primeclass”, the Lounge is open during the flight times of Emirates Airlines. Emirates Lounge is exclusively designed and overlooks the apron. The small toys, personal and hygienic kits given as a present to the young guests at the entrance make both children and their families happy. Pre-flight comfort is guaranteed with facilities including TV, Wi-Fi, daily newspapers, weekly and monthly magazines, business corner, delicious self-service buffet and bar. The Lounge also offers shower facilities, a prayer room, separate WC, disabled WC and baby changing room.

Location: Next to Gate 223 after the passport control point at the Istanbul Atatürk Airport International Terminal. ?ts closing after last flight (19:25)

Monday, Wednesday, Thursday opening : 15:20

Tuesday, Friday, Saturday opening : 12:20

HSBC Club Lounge

Designed to give maximum comfort to the customers while waiting their flights at the airport. Seating capacity is 80 people. The Lounge is open 7/24 offering a relaxing atmosphere with facilities including fresh and daily food & beverages, Wi-Fi, daily newspapers, weekly and monthly magazines, PC, TV, ATM, mobile phone charge units, locked case units, WC. HSBC Credit Card and Priority Pass Card holders can benefit from the Lounge services.

Location: One floor up to the Food Court after the passport control at the International Terminal Departures Floor.

Domestic Terminal

"primeclass" Lounge

Open 24/7, the Lounge offers a spacious and quite atmosphere overlooking the apron and amenities such as daily newspapers, weekly and monthly magazines, an open buffet, cable and wireless internet access and complimentary use of tablet computers. The Lounge stands out as the only one at the airport with an outdoor terrace area.

Location: Mezzanine Floor after the security control at the Departures Floor at Atatürk Airport Domestic Terminal.

Turkish Airlines Lounge Istanbul Domestic

The lounge occupies a 3500 square-meter area and provides seating capacity for 350 people. Besides all the comforts and modern technological facilities you might need, awaiting you as soon as you enter the lounge are delicious catering offerings.The lounge provides many services such us an always-current local and international magazine and newspaper section, Wi-Fi connectivity, media walls, power outlets for your electronic devices, private resting and showering areas, media wall, cinema, a play area for children, a prayer room, a teleconference hall, and massage service.

My emphasis.