It seems most of the adoption birth mom scams (potential birth moms not really placing babies) have had several of the following warning signs. Just because one of these signs exist does NOT mean it is a scam. Just be careful and be wise. Always use a licensed adoption agency, lawyer or facilitator. Check reference of any agency, attorney or facilitator as well. 
Please verify all facts given you by a prospective birth mom.

1. The birth mom wants money! Not all scammers want money. Some do it only for the attention. Only give money through a licensed attorney, agency or facilitator. Do not give money directly to a birth mother.

2. The birth mom has several crisis emergencies. Or drops hints that she needs money for food, rent, payments or needs but does not ask for money directly.

3. The birth mom wants to bring the baby TO you. Most real birth moms want you to come to them. This is used to get you to buy plane tickets for them that they can then cash in later. Many families have lost money by purchasing plane tickets. 

4. The birth mom is not available by phone or address is not verifiable. She only wants to call you. Always verify these with caller ID or at 411.com. You can verify addresses through the post office when asking for a zip code.

5. She misses or breaks several scheduled talks or meetings. Her reasons will always sound legit.

6. She does not send proof or pregnancy or other requested documents. She seems to always have a reason for not sending you identifying information. A sudden miscarriage or hospitalization when you ask for too much info.

7. She does not know who the birth father is. She does not want you to contact anyone else concerning her pregnancy. She will not give you real names or numbers of doctors.

8. She is unwilling to meet or talk to your attorney/agency.

9. She puts you off about  certain details. She is vague. Or she gets quiet when you talk about certain details like lawyers or signing away parental rights etc.

10. Her story has more than one version. She changes what she wants and needs in the adoption.

11. The baby is twins or a girl! Most often this is the case for many scammers.